foundation2 (phase 5a): contracts, stubs, hooks & UI wiring for lanes E/F/G

- DB: paths table (contract #3) + helpers; patch_anchor (label/color)
- API: GET /api/beats, POST /api/director (valid-empty degradation),
  /api/paths CRUD (validated POST -> 422), PATCH /api/anchors/{id};
  manifest gains capsule:false (test_api.py key-set lock updated consciously)
- CLI: features | direct | capsule subcommands -> lane stubs (exit-2 degradation)
- Backend stubs with frozen contracts in docstrings: audio_features, director, capsule
- Frontend: six lane stub modules imported from main.js; all phase-5 buttons
  pre-wired hidden in index.html; write-ui/body.capsule read-only mode;
  __F4D_API_BASE__ runtime override in state.js
- Hooks (contract #6): transport.captureAudioStream/releaseAudioStream,
  scene3d.focusOn, scene3d.setHelpersVisible (+registerHelper; camPath gizmos)
- Suite 121 -> 127 passed; npm build clean; live-browser verified (status file)

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

backend/festival4d/api.py

@@ -12,6 +12,17 @@ Serves the synthetic project fully so lane C can treat this API as finished:
     POST /api/events/detect       {t_global_s?, window_s?}  -> runs M7 detection
     POST /api/annotations         {video_id, t_video_s, bbox:[x0,y0,x1,y1]} -> {anchor_id?, point?}
 
+Phase 5 (foundation2; shapes frozen in plan/20-phase5.md contracts):
+
+    GET   /api/beats              -> beats.json body (contract #1); 404 when not yet analyzed
+    POST  /api/director           {top_n?, lead_s?} -> camPath JSON (contract #2); while lane E
+                                  is stubbed, degrades to a VALID empty path + "note"
+    GET   /api/paths              -> [{id, name, created_at}]
+    GET   /api/paths/{id}         -> {id, name, created_at, json: <parsed camPath JSON>}
+    POST  /api/paths              {name, json: <camPath JSON as text>} (validated -> 422)
+    DELETE /api/paths/{id}
+    PATCH /api/anchors/{id}       {label?, color?} -> updated anchor dict
+
 Source videos in ``data/raw`` are mounted at ``/media`` via Starlette ``StaticFiles``,
 which supports HTTP Range (required for ``<video>`` seeking; verify ``curl -H "Range:
 bytes=0-100"`` -> 206). Stubbed lane entrypoints (events detection, M8 annotation
@@ -91,6 +102,22 @@ class EventPatch(BaseModel):
     confidence: float | None = None
 
 
+class AnchorPatch(BaseModel):
+    label: str | None = None
+    color: str | None = None
+
+
+class DirectorIn(BaseModel):
+    top_n: int = 8
+    lead_s: float = 2.0
+
+
+class PathIn(BaseModel):
+    # Wire key is "json" (contract #3); aliased because `json` shadows a BaseModel attr.
+    name: str
+    path_json: str = Field(alias="json")
+
+
 # ---------------------------------------------------------------------------
 # Serialization helpers
 # ---------------------------------------------------------------------------
@@ -156,6 +183,9 @@ def manifest() -> dict:
         "has_capture": capture.capture_enabled(),
         "has_poses": db.has_poses(),
         "has_splat": config.SPLAT_PLY.exists(),
+        # Always False from the live server; the capsule (M17) bakes a manifest with true,
+        # which makes the frontend hide all write UI (phase-5 contract #5).
+        "capsule": False,
     }
 
 
@@ -333,6 +363,102 @@ def _existing_event_anchor_id(event_id: int) -> int | None:
     return None
 
 
+# ---------------------------------------------------------------------------
+# Phase 5 (foundation2). Shapes are frozen in plan/20-phase5.md "Contracts".
+# ---------------------------------------------------------------------------
+@app.get("/api/beats")
+def get_beats() -> dict:
+    """The beats.json analysis (contract #1). 404 until `python -m festival4d features` runs."""
+    import json
+
+    if not config.BEATS_JSON.exists():
+        raise HTTPException(status_code=404, detail="no beat analysis (run `python -m festival4d features`)")
+    return json.loads(config.BEATS_JSON.read_text())
+
+
+@app.post("/api/director")
+def run_director(payload: DirectorIn) -> dict:
+    """Auto-director (M11) -> camPath JSON. Degrades to a valid EMPTY path while stubbed,
+    so the response always round-trips through camPath.fromJSON (contract #2)."""
+    from festival4d import director
+
+    try:
+        return director.generate_path(top_n=payload.top_n, lead_s=payload.lead_s)
+    except NotImplementedError as exc:
+        log.info("auto-director not implemented yet: %s", exc)
+        return {"version": 1, "keyframes": [], "note": "auto-director not implemented yet (lane E / M11)"}
+
+
+def _validate_campath(text: str) -> None:
+    """422 unless ``text`` is the frozen camPath JSON (contract #2). Lane G owns hardening."""
+    import json
+
+    try:
+        data = json.loads(text)
+    except ValueError:
+        raise HTTPException(status_code=422, detail="path json is not valid JSON")
+    ok = (
+        isinstance(data, dict)
+        and data.get("version") == 1
+        and isinstance(data.get("keyframes"), list)
+        and all(
+            isinstance(k, dict)
+            and isinstance(k.get("t_global"), (int, float))
+            and isinstance(k.get("pos"), list) and len(k["pos"]) == 3
+            and isinstance(k.get("quat"), list) and len(k["quat"]) == 4
+            and isinstance(k.get("fov"), (int, float))
+            for k in data.get("keyframes", [])
+        )
+    )
+    if not ok:
+        raise HTTPException(status_code=422, detail="not a camPath JSON (see plan/20-phase5.md contract #2)")
+
+
+def _path_dict(p, with_json: bool = False) -> dict:
+    import json
+
+    d = {"id": p.id, "name": p.name, "created_at": p.created_at}
+    if with_json:
+        d["json"] = json.loads(p.path_json)
+    return d
+
+
+@app.get("/api/paths")
+def get_paths() -> list[dict]:
+    return [_path_dict(p) for p in db.get_paths()]
+
+
+@app.get("/api/paths/{path_id}")
+def get_path(path_id: int) -> dict:
+    p = db.get_path(path_id)
+    if p is None:
+        raise HTTPException(status_code=404, detail=f"no path with id={path_id}")
+    return _path_dict(p, with_json=True)
+
+
+@app.post("/api/paths")
+def create_path(payload: PathIn) -> dict:
+    _validate_campath(payload.path_json)
+    return _path_dict(db.add_path(payload.name, payload.path_json), with_json=True)
+
+
+@app.delete("/api/paths/{path_id}")
+def delete_path(path_id: int) -> dict:
+    if not db.delete_path(path_id):
+        raise HTTPException(status_code=404, detail=f"no path with id={path_id}")
+    return {"deleted": path_id}
+
+
+@app.patch("/api/anchors/{anchor_id}")
+def patch_anchor(anchor_id: int, payload: AnchorPatch) -> dict:
+    """Rename / recolor an anchor in place (M13, contract #4)."""
+    try:
+        anchor = db.patch_anchor(anchor_id, label=payload.label, color=payload.color)
+    except KeyError:
+        raise HTTPException(status_code=404, detail=f"no anchor with id={anchor_id}")
+    return _anchor_dict(anchor)
+
+
 @app.delete("/api/anchors/{anchor_id}")
 def delete_anchor(anchor_id: int) -> dict:
     """Remove an anchor (M8 / Phase 4). Unlinks any annotations that resolved to it."""

backend/festival4d/audio_features.py

@@ -0,0 +1,25 @@
+"""Audio features: beats & onsets (spec M10, lane E). STUB — lane E fills the body.
+
+Contract (frozen at foundation2 merge — phase-5 contract #1):
+
+:func:`run_features` loads the **reference** video's ingest WAV (16 kHz mono from
+``config.AUDIO_DIR``; the reference timeline *is* ``t_global``), runs beat/tempo tracking
+and onset-strength detection (librosa is already a dependency), and writes
+``config.BEATS_JSON``::
+
+    {"tempo_bpm": float | null,
+     "beats_s": [float, ...],
+     "onsets": [{"t_global_s": float, "strength": float 0..1}, ...],
+     "generated_by": "festival4d.audio_features"}
+
+All times are ``t_global`` seconds. Quiet / short / beatless audio must produce a
+*valid, empty* result (``tempo_bpm: null``, empty lists) — never a crash. Returns a
+small summary dict for the CLI log. ``GET /api/beats`` serves the written file.
+"""
+
+from __future__ import annotations
+
+
+def run_features() -> dict:
+    """Analyze the reference soundtrack and write ``data/work/beats.json`` (see module doc)."""
+    raise NotImplementedError("audio features (lane E / M10)")

backend/festival4d/capsule.py

@@ -0,0 +1,28 @@
+"""Memory capsule: zero-backend shareable export (spec M17, lane G). STUB — lane G fills.
+
+Contract: :func:`build_capsule` writes a self-contained bundle to ``out_dir`` (default
+``config.CAPSULE_DIR``):
+
+- copy ``frontend/dist`` (error clearly if missing — tell the user to ``npm run build``);
+- copy media from ``config.RAW_DIR``;
+- bake every read-only API response to files at the *same relative paths*
+  (``api/manifest``, ``api/events``, ``api/anchors``, ``api/beats``,
+  ``api/videos/{id}/poses``, ``api/pointcloud``, ``api/splat``, ``api/audio/{id}`` —
+  extracting audio via ``ingest.extract_audio_hq`` if not yet cached);
+- inject ``<script>window.__F4D_API_BASE__=""</script>`` into the copied ``index.html``;
+- set ``"capsule": true`` in the baked manifest (the frontend hides all write UI);
+- ship a stdlib ``serve.py`` in the bundle root that serves with HTTP Range support
+  (video seeking needs 206s; plain ``http.server`` can't — pitfall #4).
+
+Skip what doesn't exist (no splat -> no ``api/splat``) — degrade, don't block.
+Returns a summary dict (bundle path, file count, bytes) for the CLI log.
+"""
+
+from __future__ import annotations
+
+from pathlib import Path
+
+
+def build_capsule(out_dir: str | Path | None = None) -> dict:
+    """Build the static shareable bundle (see module doc)."""
+    raise NotImplementedError("memory capsule (lane G / M17)")

backend/festival4d/cli.py

@@ -4,7 +4,8 @@ FROZEN after foundation. Lanes fill in the bodies of the functions this dispatch
 to (in ``ingest.py``, ``audio_sync.py``, ``sfm.py``, ``events_ai.py``); they never
 edit this file or ``api.py``.
 
-Subcommands: ``synthetic | ingest | sync | reconstruct | events | serve``.
+Subcommands: ``synthetic | ingest | sync | reconstruct | events | features | direct |
+capsule | serve``.
 
 Every subcommand dispatches to a single lane entrypoint. While a lane is still a stub,
 its entrypoint raises :class:`NotImplementedError`; we catch that here and print a clear
@@ -57,6 +58,32 @@ def _cmd_events(args: argparse.Namespace) -> int:
     return 0
 
 
+def _cmd_features(args: argparse.Namespace) -> int:
+    from festival4d import audio_features
+
+    result = audio_features.run_features()
+    log.info("features: %s", result)
+    return 0
+
+
+def _cmd_direct(args: argparse.Namespace) -> int:
+    import json
+
+    from festival4d import director
+
+    path = director.generate_path(top_n=args.top_n, lead_s=args.lead_s)
+    print(json.dumps(path, indent=2))
+    return 0
+
+
+def _cmd_capsule(args: argparse.Namespace) -> int:
+    from festival4d import capsule
+
+    result = capsule.build_capsule(out_dir=args.out)
+    log.info("capsule: %s", result)
+    return 0
+
+
 def _cmd_serve(args: argparse.Namespace) -> int:
     import uvicorn
 
@@ -97,6 +124,20 @@ def build_parser() -> argparse.ArgumentParser:
                        help="window width in seconds when --t-global-s is given")
     p_evt.set_defaults(func=_cmd_events)
 
+    p_feat = sub.add_parser("features", help="beat/onset analysis of the reference audio (lane E / M10)")
+    p_feat.set_defaults(func=_cmd_features)
+
+    p_dir = sub.add_parser("direct", help="auto-director: events -> camPath JSON on stdout (lane E / M11)")
+    p_dir.add_argument("--top-n", dest="top_n", type=int, default=8,
+                       help="number of top-confidence events to cover (default 8)")
+    p_dir.add_argument("--lead-s", dest="lead_s", type=float, default=2.0,
+                       help="seconds of lead-in before each event (default 2.0)")
+    p_dir.set_defaults(func=_cmd_direct)
+
+    p_cap = sub.add_parser("capsule", help="bake a zero-backend shareable bundle (lane G / M17)")
+    p_cap.add_argument("--out", default=None, help="output dir (default data/capsule/)")
+    p_cap.set_defaults(func=_cmd_capsule)
+
     p_srv = sub.add_parser("serve", help="run the FastAPI app (M3)")
     p_srv.add_argument("--host", default=config.API_HOST)
     p_srv.add_argument("--port", type=int, default=config.API_PORT)

backend/festival4d/config.py

@@ -40,6 +40,8 @@ FRAMES_DIR = WORK_DIR / "frames"    # sampled JPEGs for SfM
 COLMAP_DIR = WORK_DIR / "colmap"    # COLMAP workspace
 DB_PATH = DATA_DIR / "project.db"   # SQLite (gitignored)
 
+BEATS_JSON = WORK_DIR / "beats.json"        # beat/onset analysis (lane E / M10, /api/beats)
+CAPSULE_DIR = DATA_DIR / "capsule"          # default output of `python -m festival4d capsule` (M17)
 POINTS_PLY = WORK_DIR / "points.ply"        # reconstructed / synthetic point cloud
 SPLAT_PLY = WORK_DIR / "splat.ply"          # optional 3DGS splat (trained externally, e.g. via MODELBEAST — see docs/modelbeast-crossover.md); viewer prefers it over the point cloud
 SYNC_JSON = WORK_DIR / "sync.json"          # exported sync solution (lane A)

backend/festival4d/db.py

@@ -12,6 +12,7 @@ Schema (spec §2)::
     anchors(id, label, x,y,z, color)
     events(id, t_global_s, duration_s, event_type, confidence, description, source)
     annotations(id, video_id FK, t_video_s, x0,y0,x1,y1, resolved_anchor_id FK NULL)
+    paths(id, name, created_at, path_json)    # phase 5 (M16): saved camPath JSON, as text
 
 Engine management: :func:`init_engine` (re)binds the module to a SQLite file. It defaults
 to ``config.DB_PATH`` but tests point it at a temp file. Helpers open and commit their own
@@ -129,6 +130,19 @@ class Annotation(Base):
     )
 
 
+class SavedPath(Base):
+    """A saved keyframed camera path (phase 5 contract #3). ``path_json`` is the frozen
+    camPath JSON (``{"version": 1, "keyframes": [...]}``) stored verbatim as text —
+    the DB never interprets it beyond POST-time validation in the API layer."""
+
+    __tablename__ = "paths"
+
+    id: Mapped[int] = mapped_column(Integer, primary_key=True)
+    name: Mapped[str] = mapped_column(String, nullable=False)
+    created_at: Mapped[str] = mapped_column(String, nullable=False)
+    path_json: Mapped[str] = mapped_column(String, nullable=False)
+
+
 # ---------------------------------------------------------------------------
 # Engine / session management
 # ---------------------------------------------------------------------------
@@ -350,6 +364,24 @@ def update_anchor(
         return anchor
 
 
+def patch_anchor(anchor_id: int, label: str | None = None, color: str | None = None) -> Anchor:
+    """Rename / recolor an anchor without moving it (phase 5 contract #4, M13).
+
+    Only provided fields change. Raises ``KeyError`` if the id is unknown.
+    """
+    with session_scope() as s:
+        anchor = s.get(Anchor, anchor_id)
+        if anchor is None:
+            raise KeyError(f"no anchor with id={anchor_id}")
+        if label is not None:
+            anchor.label = label
+        if color is not None:
+            anchor.color = color
+        s.flush()
+        s.refresh(anchor)
+        return anchor
+
+
 def delete_anchor(anchor_id: int) -> bool:
     """Delete an anchor, first unlinking any annotations that resolved to it.
 
@@ -444,6 +476,38 @@ def update_event(
         return event
 
 
+# ---------------------------------------------------------------------------
+# Saved camera paths (phase 5 / M16)
+# ---------------------------------------------------------------------------
+def add_path(name: str, path_json: str) -> SavedPath:
+    with session_scope() as s:
+        path = SavedPath(name=name, path_json=path_json, created_at=_now_iso())
+        s.add(path)
+        s.flush()
+        s.refresh(path)
+        return path
+
+
+def get_paths() -> list[SavedPath]:
+    with session_scope() as s:
+        return list(s.scalars(select(SavedPath).order_by(SavedPath.id)))
+
+
+def get_path(path_id: int) -> SavedPath | None:
+    with session_scope() as s:
+        return s.get(SavedPath, path_id)
+
+
+def delete_path(path_id: int) -> bool:
+    """Delete a saved path. Returns ``True`` if a row was deleted, ``False`` if unknown."""
+    with session_scope() as s:
+        path = s.get(SavedPath, path_id)
+        if path is None:
+            return False
+        s.delete(path)
+        return True
+
+
 # ---------------------------------------------------------------------------
 # Annotations
 # ---------------------------------------------------------------------------

backend/festival4d/director.py

@@ -0,0 +1,25 @@
+"""Auto-director: events -> keyframed camera path (spec M11, lane E). STUB — lane E fills.
+
+Contract (frozen at foundation2 merge — phase-5 contract #2): :func:`generate_path`
+returns a **camPath-compatible** dict::
+
+    {"version": 1,
+     "keyframes": [{"t_global": float, "pos": [x, y, z], "quat": [x, y, z, w], "fov": float}]}
+
+Poses are **Three.js scene space**, quaternion order **[x, y, z, w]** — convert from the
+COLMAP rows via :func:`festival4d.geometry.colmap_to_threejs`, never inline (pitfall #1).
+
+Deterministic v1 rules — no ML: take the top-N events by confidence (ties -> earlier);
+for each, choose the registered camera with a pose nearest the event time; keyframes at
+``t_event - lead_s`` and ``t_event + duration``; when ``config.BEATS_JSON`` exists, snap
+keyframe times to the nearest beat (no beats file -> no snapping — degrade, don't block);
+FOV from that camera's intrinsics (``2 * atan(height / (2 * fy))`` in degrees, the same
+formula as ``scene3d.snapTo``).
+"""
+
+from __future__ import annotations
+
+
+def generate_path(top_n: int = 8, lead_s: float = 2.0) -> dict:
+    """Build a camPath JSON dict from the detected events (see module doc)."""
+    raise NotImplementedError("auto-director (lane E / M11)")

backend/tests/test_api.py

@@ -34,8 +34,9 @@ def test_manifest_shape(client):
     data = client.get("/api/manifest").json()
     # Exact-set lock: additive manifest fields are fine, but must be added here consciously
     # (this assertion has already caught two silent drifts — has_splat and has_capture).
-    assert set(data) == {"videos", "t_global_max", "has_poses", "has_splat", "has_capture"}
+    assert set(data) == {"videos", "t_global_max", "has_poses", "has_splat", "has_capture", "capsule"}
     assert data["has_poses"] is True
+    assert data["capsule"] is False  # live server is never a capsule (M17 bakes true)
     assert data["has_capture"] is False  # capture routes are opt-in (FESTIVAL4D_CAPTURE)
     assert len(data["videos"]) == 3
     v = data["videos"][0]

backend/tests/test_phase5_api.py

@@ -0,0 +1,107 @@
+"""Phase-5 foundation2 contract tests: the new route shapes lanes E/F/G depend on
+(plan/20-phase5.md "Contracts"). Lane G deepens paths coverage in test_paths.py;
+lane E owns the real beats/director behavior tests.
+"""
+
+from __future__ import annotations
+
+import json
+import shutil
+
+import pytest
+
+pytestmark = pytest.mark.skipif(
+    shutil.which("ffmpeg") is None or shutil.which("ffprobe") is None,
+    reason="ffmpeg/ffprobe required to build the API test fixture",
+)
+
+CAMPATH = {
+    "version": 1,
+    "keyframes": [
+        {"t_global": 1.0, "pos": [0, 1, 5], "quat": [0, 0, 0, 1], "fov": 50},
+        {"t_global": 4.0, "pos": [2, 1, 4], "quat": [0, 0.3826834, 0, 0.9238795], "fov": 42},
+    ],
+}
+
+
+@pytest.fixture(scope="module")
+def client():
+    from fastapi.testclient import TestClient
+
+    from festival4d import synthetic
+
+    synthetic.build(duration_s=1.0, run_ffmpeg=True)  # into the temp data dir (conftest)
+
+    from festival4d import api
+
+    with TestClient(api.app) as c:
+        yield c
+
+
+def test_beats_404_then_serves_file(client):
+    from festival4d import config
+
+    config.BEATS_JSON.unlink(missing_ok=True)
+    assert client.get("/api/beats").status_code == 404
+    body = {"tempo_bpm": 120.0, "beats_s": [0.5, 1.0], "onsets": [], "generated_by": "festival4d.audio_features"}
+    config.BEATS_JSON.parent.mkdir(parents=True, exist_ok=True)
+    config.BEATS_JSON.write_text(json.dumps(body))
+    try:
+        assert client.get("/api/beats").json() == body
+    finally:
+        config.BEATS_JSON.unlink()
+
+
+def test_director_degrades_to_valid_empty_campath(client):
+    # While lane E is stubbed the response must still round-trip through camPath.fromJSON:
+    # a valid version-1 path with zero keyframes, plus a "note" marking the degradation.
+    data = client.post("/api/director", json={}).json()
+    assert data["version"] == 1
+    assert data["keyframes"] == []
+    assert "note" in data
+    assert client.post("/api/director", json={"top_n": 3, "lead_s": 1.0}).status_code == 200
+
+
+def test_paths_crud_roundtrip(client):
+    assert client.get("/api/paths").json() == []
+    created = client.post(
+        "/api/paths", json={"name": "sweep", "json": json.dumps(CAMPATH)}
+    ).json()
+    assert set(created) == {"id", "name", "created_at", "json"}
+    assert created["json"] == CAMPATH  # deep-equal roundtrip
+    pid = created["id"]
+
+    listing = client.get("/api/paths").json()
+    assert [set(p) for p in listing] == [{"id", "name", "created_at"}]
+    assert client.get(f"/api/paths/{pid}").json()["json"] == CAMPATH
+
+    assert client.delete(f"/api/paths/{pid}").json() == {"deleted": pid}
+    assert client.get(f"/api/paths/{pid}").status_code == 404
+    assert client.delete(f"/api/paths/{pid}").status_code == 404
+
+
+def test_paths_post_validates_campath(client):
+    post = lambda body: client.post("/api/paths", json={"name": "bad", "json": body}).status_code
+    assert post("not json at all {") == 422
+    assert post(json.dumps({"version": 2, "keyframes": []})) == 422
+    assert post(json.dumps({"version": 1})) == 422
+    assert post(json.dumps({"version": 1, "keyframes": [{"t_global": 0}]})) == 422
+
+
+def test_anchor_patch_label_and_color(client):
+    a = client.post("/api/anchors", json={"label": "F", "x": 0, "y": 0, "z": 0}).json()
+    patched = client.patch(f"/api/anchors/{a['id']}", json={"label": "Fred", "color": "#4dd0ff"}).json()
+    assert patched["label"] == "Fred" and patched["color"] == "#4dd0ff"
+    assert (patched["x"], patched["y"], patched["z"]) == (0, 0, 0)  # position untouched
+    # partial patch: color-only leaves the label alone
+    assert client.patch(f"/api/anchors/{a['id']}", json={"color": "#fff"}).json()["label"] == "Fred"
+    assert client.patch("/api/anchors/99999", json={"label": "x"}).status_code == 404
+
+
+def test_cli_dispatches_stubs_gracefully():
+    # The three new subcommands exist and degrade per the house pattern: exit code 2,
+    # no traceback, while their lane entrypoints are stubs.
+    from festival4d import cli
+
+    for cmd in (["features"], ["direct"], ["capsule"]):
+        assert cli.main(cmd) == 2

frontend/index.html

@@ -197,6 +197,10 @@
         pointer-events: none; z-index: 6; border-radius: 2px;
       }
 
+      /* Capsule mode (M17, phase-5 contract #5): a static baked bundle has no write API, so
+         everything marked .write-ui disappears when main.js sets body.capsule from the manifest. */
+      body.capsule .write-ui { display: none !important; }
+
       /* Loading / error */
       #loading {
         position: fixed; inset: 0; display: flex; align-items: center; justify-content: center;
@@ -228,13 +232,32 @@
             <button class="btn" id="btn-path-export" title="Export path as JSON">⤓</button>
             <button class="btn" id="btn-path-import" title="Import path JSON">⤒</button>
             <button class="btn" id="btn-path-clear" title="Clear all keyframes">✕</button>
+            <!-- Phase 5: hidden until the owning lane's module reports ready (plan/20-phase5.md) -->
+            <button class="btn" id="btn-director" style="display:none"
+                    title="Auto-director: build a camera path from the detected events (M11)">🎬 Auto-path</button>
+            <button class="btn write-ui" id="btn-path-save" style="display:none"
+                    title="Save the current camera path to the project (M16)">💾</button>
+            <select class="btn" id="path-load-select" style="display:none"
+                    title="Load a saved camera path (M16)"></select>
+            <button class="btn write-ui" id="btn-path-del" style="display:none"
+                    title="Delete the selected saved path (M16)">🗑</button>
             <span class="ctl-sep"></span>
             <button class="btn" id="btn-spatial" style="display:none"
                     title="Spatial audio: hear every camera from its position in the scene">🎧 3D audio</button>
+            <button class="btn" id="btn-export" style="display:none"
+                    title="Export the camera path as a cinematic webm (M12)">⏺ Export</button>
+            <button class="btn" id="btn-photo" style="display:none"
+                    title="Photo mode: hi-res still of the 3D scene (M14, P)">📷</button>
+            <button class="btn" id="btn-fx" style="display:none"
+                    title="Moment FX: bursts and pulses on event markers (M15)">✨</button>
+            <button class="btn" id="btn-anchors" style="display:none"
+                    title="Anchors & friend tags (M13)">⚓</button>
             <input type="file" id="path-file" accept="application/json,.json" hidden />
           </div>
           <div id="scene-hint">drag to orbit · 1–9 snap to camera · K add keyframe · Esc detach</div>
-          <div id="annot-panel"></div>
+          <div id="annot-panel" class="write-ui"></div>
+          <!-- M13 anchor manager mounts here (lane F); hidden until anchorPanel.js is filled -->
+          <div id="anchor-panel" style="display:none"></div>
         </div>
         <div id="grid-pane">
           <div id="video-grid"></div>

frontend/src/anchorPanel.js

@@ -0,0 +1,19 @@
+// Anchor manager & friend tags (spec M13, lane F). STUB — lane F fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden ⚓ toggle (#btn-anchors) and the empty #anchor-panel
+// container in index.html, this module's import + init() call in main.js, the hooks
+// `scene3d.focusOn(x, y, z)` (jump-to) and `PATCH ${state.apiBase}/api/anchors/{id}`
+// {label?, color?} (rename/recolor), plus DELETE /api/anchors/{id} from phase 4.
+//
+// When implementing: unhide the button, set `ready = true`; build the collapsible list
+// (color dot, label, jump-to, rename, recolor, delete) from state.anchors; after any
+// mutation update state.anchors and emit("anchors-changed") so scene3d + overlays refresh.
+// The ＋ Tag flow reuses the M8 bbox-annotation flow WITHOUT an event (annotate.js is
+// frozen — drive it, don't edit it) and names the resulting anchor.
+// Capsule mode: give every MUTATING control the `write-ui` class — body.capsule hides that
+// class globally (contract #5); the read-only list + jump-to stay available.
+
+export const anchorPanel = {
+  ready: false,
+  init() {}, // ponytail: stub — lane F replaces the body
+};

frontend/src/camPath.js

@@ -27,6 +27,7 @@ export class CamPath {
     if (!this.group) {
       this.group = new THREE.Group();
       scene3d.addObject(this.group);
+      scene3d.registerHelper(this.group); // keyframe gizmos hide with the helpers (M14)
     }
   }
 

frontend/src/director.js

@@ -0,0 +1,16 @@
+// Auto-director UI (spec M11, lane E). STUB — lane E fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden 🎬 button (#btn-director in index.html), and this
+// module's import + init() call in main.js. main.js does NOT wire the click — you do,
+// inside init().
+//
+// When implementing: unhide the button (el.style.display = ""), set `ready = true`; on click
+// POST {top_n?, lead_s?} to `${state.apiBase}/api/director` and load the response with
+// camPath.fromJSON(...) — never edit camPath.js (frozen). The response is ALWAYS a valid
+// camPath JSON; zero keyframes means "no events yet / stubbed" — surface that in the UI,
+// don't crash (pitfall #5). Play it via the existing #btn-path flow.
+
+export const director = {
+  ready: false, // flips to true when the lane implements this module
+  init() {}, // ponytail: stub — lane E replaces the body
+};

frontend/src/exportVideo.js

@@ -0,0 +1,18 @@
+// Cinematic export (spec M12, lane E). STUB — lane E fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden ⏺ button (#btn-export in index.html), this module's
+// import + init() call in main.js, and the transport hooks
+// `transport.captureAudioStream()` -> MediaStream tapping the live WebAudio mix (post-gain,
+// spatial included) and `transport.releaseAudioStream()` when done.
+//
+// When implementing: unhide the button, set `ready = true`; on click seek to the first
+// camPath keyframe, play the path, mux scene3d canvas `captureStream(30)` + the audio stream
+// with MediaRecorder (video/webm;codecs=vp9,opus), stop at the last keyframe, download
+// `festival4d-cut.webm`, then RESTORE all prior UI/transport state. The canvas is
+// `scene3d.renderer.domElement`. MediaRecorder needs a *focused* tab to capture real frames
+// (pitfall #2) — say so in your evidence if you couldn't.
+
+export const exportVideo = {
+  ready: false,
+  init() {}, // ponytail: stub — lane E replaces the body
+};

frontend/src/fx.js

@@ -0,0 +1,19 @@
+// Moment FX (spec M15, lane F). STUB — lane F fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden ✨ toggle (#btn-fx in index.html), this module's
+// import + init() call in main.js, and a per-frame `fx.update(tGlobal)` call from the master
+// loop (after transport.tick(), before scene3d.update()).
+//
+// When implementing: unhide the button, set `ready = true`. update() watches the playhead
+// crossing event markers (state.events) — detect crossings in play AND scrub (track the
+// previous tGlobal; a seek emits "seek" if you need to reset). On `pyro`/`confetti` fire a
+// short particle burst at the event's resolved anchor, falling back to the stage centroid;
+// on `bass_drop` pulse the point-cloud/splat scale for ~a beat (beats via GET /api/beats
+// when present — no beats file, use ~0.5 s; pitfall #5). Scene access ONLY through
+// scene3d.addObject/removeObject. Keep >= 30 fps on the synthetic scene.
+
+export const fx = {
+  ready: false,
+  init() {}, // ponytail: stub — lane F replaces the body
+  update(tGlobal) {}, // called every animation frame by main.js
+};

frontend/src/main.js

@@ -16,6 +16,15 @@ import { scene3d, videoColor } from "./scene3d.js";
 import { timeline } from "./timeline.js";
 import { annotator } from "./annotate.js";
 import { camPath } from "./camPath.js";
+// Phase-5 lane modules (stubs until lanes E/F/G fill them; each wires its own hidden button).
+import { director } from "./director.js";
+import { exportVideo } from "./exportVideo.js";
+import { anchorPanel } from "./anchorPanel.js";
+import { photoMode } from "./photoMode.js";
+import { fx } from "./fx.js";
+import { pathsStore } from "./pathsStore.js";
+
+const laneModules = { director, exportVideo, anchorPanel, photoMode, fx, pathsStore };
 
 async function getJSON(path) {
   const resp = await fetch(API_BASE + path);
@@ -49,6 +58,9 @@ async function boot() {
       link.style.display = "";
     }
     state.hasSplat = !!manifest.has_splat;
+    // Capsule (M17): a static baked bundle has no write API — hide everything .write-ui.
+    state.capsule = !!manifest.capsule;
+    document.body.classList.toggle("capsule", state.capsule);
     for (const v of state.videos) state.enabled[v.id] = true;
     state.audioSourceId = referenceVideoId();
 
@@ -75,8 +87,8 @@ async function boot() {
     // localStorage.setItem("f4dDebug", "1").
     if (import.meta.env?.DEV || localStorage.getItem("f4dDebug")) {
       window.__f4d = {
-        state, transport, scene3d, timeline, cells: () => cells,
-        poseAt, projectWorldToVideoPx,
+        state, transport, scene3d, timeline, camPath, cells: () => cells,
+        poseAt, projectWorldToVideoPx, ...laneModules,
       };
     }
   } catch (err) {
@@ -120,6 +132,16 @@ function buildUI() {
   wireKeyboard();
   positionVideosWhenReady();
 
+  // Phase-5 lane modules: each init() wires its own (hidden) controls and unhides them when
+  // the lane has filled the stub. A broken module degrades to its button staying hidden.
+  for (const [name, mod] of Object.entries(laneModules)) {
+    try {
+      mod.init();
+    } catch (err) {
+      console.warn(`[festival4d] lane module "${name}" init failed`, err);
+    }
+  }
+
   // Reflect follow/roam state on the free-roam button; snapping cancels a playing path.
   on("follow", (id) => {
     el("btn-roam").classList.toggle("active", id == null);
@@ -244,6 +266,7 @@ function startLoop() {
   const frame = () => {
     transport.tick();
     for (const cell of cells) drawOverlay(cell);
+    fx.update(state.tGlobal); // M15: playhead-crossing effects (no-op while stubbed)
     camPath.update(state.tGlobal); // M9: drive the viewer camera before the scene renders
     scene3d.update();
     timeline.update(state.tGlobal);

frontend/src/pathsStore.js

@@ -0,0 +1,18 @@
+// Server-side camera paths UI (spec M16, lane G). STUB — lane G fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden controls in index.html — #btn-path-save (💾),
+// #path-load-select (dropdown), #btn-path-del (🗑) — this module's import + init() call in
+// main.js, and the API: GET /api/paths (list of {id,name,created_at}),
+// GET /api/paths/{id} ({..., json: <camPath JSON>}), POST /api/paths {name, json:<text>}
+// (422 on invalid), DELETE /api/paths/{id}.
+//
+// When implementing: unhide the controls, set `ready = true`. Save = prompt for a name,
+// POST camPath.toJSON(); load = fetch the selected path and camPath.fromJSON(json); delete =
+// DELETE the selected id. Refresh the dropdown after every mutation. #btn-path-save and
+// #btn-path-del already carry the `write-ui` class, so capsule mode (contract #5) hides
+// them for free — the load dropdown may stay if you bake paths in, else hide it too.
+
+export const pathsStore = {
+  ready: false,
+  init() {}, // ponytail: stub — lane G replaces the body
+};

frontend/src/photoMode.js

@@ -0,0 +1,18 @@
+// Photo mode (spec M14, lane F). STUB — lane F fills THIS FILE ONLY.
+//
+// Pre-wired by foundation2: the hidden 📷 button (#btn-photo in index.html), this module's
+// import + init() call in main.js, and the hook `scene3d.setHelpersVisible(false)` which
+// hides grid/axes/frusta/path-lines/keyframe-gizmos/anchor-labels in one call (restore with
+// true).
+//
+// When implementing: unhide the button, set `ready = true`, bind key "P" too; on trigger
+// pause the transport, setHelpersVisible(false), render ONE frame at 3840-wide (preserve
+// aspect) to an offscreen WebGLRenderTarget via scene3d.renderer/scene/camera, download the
+// PNG, then restore everything (helpers, renderer size, play state). Works in free-roam and
+// follow-cam; with a splat present it renders the splat (no splat -> the point cloud —
+// pitfall #5).
+
+export const photoMode = {
+  ready: false,
+  init() {}, // ponytail: stub — lane F replaces the body
+};

frontend/src/scene3d.js

@@ -65,6 +65,8 @@ export class Scene3D {
     this._raf = null;
     this.anchorGroup = null; // 3D anchor spheres + labels (M6 anchors + M8 resolved)
     this.pathMode = false; // when true, camPath (M9) drives the camera; we don't touch it
+    this.helpersVisible = true; // M14 hook: grid/axes/frusta/gizmos/labels toggle
+    this._helperObjs = []; // extra helper objects registered by other modules (camPath gizmos)
   }
 
   init(canvas) {
@@ -96,6 +98,8 @@ export class Scene3D {
     this.scene.add(grid);
     const axes = new THREE.AxesHelper(1.5);
     this.scene.add(axes);
+    this._grid = grid;
+    this._axes = axes;
 
     this.anchorGroup = new THREE.Group();
     this.scene.add(this.anchorGroup);
@@ -129,12 +133,13 @@ export class Scene3D {
       if (a.label) {
         const label = makeLabelSprite(a.label);
         label.position.set(a.x, a.y + 0.3, a.z);
+        label.visible = this.helpersVisible; // photo mode (M14) may be hiding labels right now
         this.anchorGroup.add(label);
       }
     }
   }
 
-  /** Expose the scene graph for auxiliary overlays (e.g. camPath gizmos, M9). */
+  /** Expose the scene graph for auxiliary overlays (e.g. camPath gizmos M9, moment FX M15). */
   addObject(obj) {
     this.scene?.add(obj);
   }
@@ -142,6 +147,51 @@ export class Scene3D {
     this.scene?.remove(obj);
   }
 
+  /** Register an added object as a "helper" so setHelpersVisible governs it (camPath gizmos). */
+  registerHelper(obj) {
+    this._helperObjs.push(obj);
+    obj.visible = this.helpersVisible;
+  }
+
+  /**
+   * M14 hook (phase-5 contract #6): show/hide every non-content visual in one call — grid,
+   * axes, camera frusta + markers + path lines, registered gizmo groups, and anchor LABEL
+   * sprites (anchor spheres stay: friend tags belong in photos). update() keeps enforcing
+   * the flag on the per-video rigs, whose visibility it recomputes every frame.
+   */
+  setHelpersVisible(visible) {
+    this.helpersVisible = !!visible;
+    if (this._grid) this._grid.visible = this.helpersVisible;
+    if (this._axes) this._axes.visible = this.helpersVisible;
+    for (const obj of this._helperObjs) obj.visible = this.helpersVisible;
+    if (this.anchorGroup)
+      for (const child of this.anchorGroup.children)
+        if (child.isSprite) child.visible = this.helpersVisible;
+  }
+
+  /**
+   * M13 hook (phase-5 contract #6): fly the free-roam camera's attention to a world point
+   * (anchor jump-to). Detaches follow-cam / path mode, retargets OrbitControls, and backs the
+   * camera off along its current viewing direction.
+   */
+  focusOn(x, y, z, dist = 6) {
+    if (this.pathMode) this.exitPathMode();
+    if (state.followCameraId != null) {
+      state.followCameraId = null;
+      this._tween = null;
+      emit("follow", null);
+    }
+    this.camera.fov = DEFAULT_FOV;
+    this.camera.updateProjectionMatrix();
+    const dir = this.camera.position.clone().sub(this.controls.target);
+    if (dir.lengthSq() < 1e-6) dir.set(0, 0.5, 1);
+    dir.normalize().multiplyScalar(dist);
+    this.controls.target.set(x, y, z);
+    this.camera.position.set(x + dir.x, y + dir.y, z + dir.z);
+    this.controls.enabled = true;
+    this.controls.update();
+  }
+
   /** M9: hand camera control to camPath. update() then leaves the camera alone. */
   enterPathMode() {
     this.pathMode = true;
@@ -362,8 +412,8 @@ export class Scene3D {
       if (!rig) continue;
       const pose = this._livePose(v.id);
       const on = pose && state.enabled[v.id] !== false;
-      rig.group.visible = !!on;
-      if (rig.path) rig.path.visible = state.enabled[v.id] !== false;
+      rig.group.visible = !!on && this.helpersVisible;
+      if (rig.path) rig.path.visible = state.enabled[v.id] !== false && this.helpersVisible;
       if (!on) continue;
       const { matrixWorld } = colmapToThreejs(pose.q, pose.t);
       _m4.fromArray(matrixWorld);

frontend/src/state.js

@@ -7,7 +7,11 @@
 // A hosted build sets VITE_API_BASE to a same-origin path prefix (e.g. "/festifun") so every
 // request — fetch, <video> src, PLY loader — goes through the reverse proxy under that path.
 // Empty string = same-origin at root. See deploy/DEPLOY.md.
-export const API_BASE = import.meta.env.VITE_API_BASE ?? "http://localhost:8000";
+// Phase-5 contract #5: a RUNTIME override wins over the build-time value — the memory capsule
+// (M17) injects `window.__F4D_API_BASE__ = ""` into its baked index.html so the same dist
+// bundle turns zero-backend. `??` (not `||`): empty string is a valid value (same-origin).
+export const API_BASE =
+  window.__F4D_API_BASE__ ?? import.meta.env.VITE_API_BASE ?? "http://localhost:8000";
 
 export const state = {
   apiBase: API_BASE,
@@ -18,6 +22,7 @@ export const state = {
   tGlobalMax: 0,
   hasPoses: false,
   hasSplat: false, // optional 3DGS splat at /api/splat (preferred over the point cloud)
+  capsule: false, // manifest.capsule (M17): static baked bundle => hide ALL write UI
   poses: {}, // id -> [{frame_idx, t_video_s, q:[w,x,y,z], t:[x,y,z], intrinsics, registered}]
   anchors: [], // [{id, label, x, y, z, color}]
   events: [], // [{id, t_global_s, duration_s, event_type, confidence, description, source}]

frontend/src/transport.js

@@ -42,6 +42,7 @@ export class Transport {
     this._buffers = new Map(); // video id -> AudioBuffer (decoded) | null (unavailable)
     this._decoding = new Set(); // video ids with a fetch/decode in flight
     this._tracks = new Map(); // playing tracks: video id -> { src, gain, panner|null }
+    this._captureDest = null; // MediaStreamAudioDestinationNode while an export taps the mix (M12)
   }
 
   /** Register the video cells the transport drives and start their frame loops. */
@@ -296,11 +297,42 @@ export class Transport {
     } else {
       gain.connect(ctx.destination);
     }
+    if (this._captureDest) (panner ?? gain).connect(this._captureDest); // live export keeps hearing us
     if (tv >= 0) src.start(0, tv);
     else src.start(ctx.currentTime + -tv / state.rate, 0); // camera starts later than t_global
     this._tracks.set(id, { src, gain, panner });
   }
 
+  /**
+   * M12 hook (phase-5 contract #6): a MediaStream carrying the live WebAudio mix — tapped
+   * post-gain, after the spatial panner when 🎧 is on — for MediaRecorder muxing. Tracks that
+   * (re)start while the tap is live (seeks, source switches) join it automatically
+   * (_startTrack above). With no decoded track (fallback <video> audio) the stream is silent —
+   * degrade, don't block (pitfall #5). Call releaseAudioStream() when the export ends.
+   */
+  captureAudioStream() {
+    const ctx = this._ensureCtx();
+    if (!this._captureDest) {
+      this._captureDest = ctx.createMediaStreamDestination();
+      for (const { gain, panner } of this._tracks.values())
+        (panner ?? gain).connect(this._captureDest);
+    }
+    return this._captureDest.stream;
+  }
+
+  /** Drop the M12 export tap (the matching half of captureAudioStream()). */
+  releaseAudioStream() {
+    if (!this._captureDest) return;
+    for (const { gain, panner } of this._tracks.values()) {
+      try {
+        (panner ?? gain).disconnect(this._captureDest);
+      } catch {
+        /* already disconnected */
+      }
+    }
+    this._captureDest = null;
+  }
+
   /**
    * 🎧 Per-frame 3D audio update (called by scene3d): the listener follows the viewer camera
    * and each playing track's panner sits at its camera's current pose. Takes plain numbers in

plan/20-phase5.md

@@ -172,7 +172,7 @@ structure, baked-JSON validity, and serve.py Range (206) behavior.
 |---|---|
 | Lane E | `backend/festival4d/audio_features.py`, `director.py`, `backend/tests/test_audio_features.py`, `test_director.py`, `frontend/src/director.js`, `exportVideo.js` |
 | Lane F | `frontend/src/anchorPanel.js`, `photoMode.js`, `fx.js` |
-| Lane G | `backend/festival4d/capsule.py`, `backend/tests/test_paths.py`, `test_capsule.py`, `frontend/src/pathsStore.js`, the paths-route bodies in the area foundation2 marks for lane G |
+| Lane G | `backend/festival4d/capsule.py`, `backend/tests/test_paths.py`, `test_capsule.py`, `frontend/src/pathsStore.js` — the paths-route bodies were CRUD one-liners over the db helpers, so foundation2 implemented them (basic tests in `test_phase5_api.py`); lane G owns deepening `test_paths.py` + the UI |
 | Every agent | its own `plan/status/<lane>.md` |
 | **Coordinator only** | `plan/DIRECTIVES.md` |
 | **Frozen during 5b** | contract item 7 above |

plan/status/foundation2.md

@@ -0,0 +1,55 @@
+# Status — foundation2
+
+## Round 1 — 2026-07-17 — STATUS: ready_to_merge
+
+**Directives acknowledged:** Round 4 of plan/DIRECTIVES.md. Single-agent phase 5a — main
+working directory on branch `foundation2` (per directive 3).
+
+**Acceptance checklist** (plan/20-phase5.md "foundation2 scope"):
+- [x] DB: `paths` table (contract #3) + helpers `add/get/get_one/delete_path`, plus
+      `patch_anchor` (label/color only) — `db.py`
+- [x] API: `GET /api/beats` (serves `config.BEATS_JSON`, 404 when absent),
+      `POST /api/director` (degrades to a VALID empty camPath + `note` while lane E is
+      stubbed), `GET/POST/DELETE /api/paths*` (implemented — CRUD over the helpers was
+      cheaper than stubbing; POST validates the camPath shape → 422),
+      `PATCH /api/anchors/{id}` (contract #4) — `api.py`
+- [x] Manifest gained `"capsule": false` — `test_api.py` exact-set lock updated in the same
+      commit (pitfall #3)
+- [x] CLI: `features`, `direct`, `capsule` subcommands dispatch into stubs; house
+      degradation (exit 2, no traceback) — `cli.py`
+- [x] Backend stubs raise NotImplementedError with the frozen contract in the docstring:
+      `audio_features.py`, `director.py`, `capsule.py`
+- [x] Frontend stub modules created + imported from `main.js`, each wiring its own hidden
+      button in init(): `director.js`, `exportVideo.js`, `anchorPanel.js`, `photoMode.js`
+      (+ per-frame `fx.update()` call in the master loop), `fx.js`, `pathsStore.js`
+- [x] index.html: ALL phase-5 buttons pre-wired hidden — #btn-director, #btn-path-save,
+      #path-load-select, #btn-path-del, #btn-export, #btn-photo, #btn-fx, #btn-anchors,
+      #anchor-panel container; `.write-ui` class + `body.capsule .write-ui{display:none}`
+- [x] Hooks (contract #6): `transport.captureAudioStream()/releaseAudioStream()` (post-gain
+      tap, spatial included, tracks re-join across seeks), `scene3d.focusOn(x,y,z)`,
+      `scene3d.setHelpersVisible(bool)` (+ `registerHelper`; camPath gizmos registered)
+- [x] `state.js`: `window.__F4D_API_BASE__` ?? `VITE_API_BASE` ?? localhost (contract #5);
+      `state.capsule` from the manifest toggles `body.capsule`
+- [x] Suite ≥ 121 + new tests: **127 passed** (121 floor + 6 in `test_phase5_api.py`)
+- [x] Ownership table updated (paths-route bodies → foundation2; noted in 20-phase5.md)
+
+**Done this round — evidence:**
+- `uv run pytest backend/tests` → **127 passed** (was 121).
+- `npm run build` → clean (pre-existing chunk-size warning only).
+- Live browser (Vite :5173 + uvicorn :8000, synthetic fixture): app boots (3 videos, sync
+  +0 ms); all 9 new controls present and `display:none`; `setHelpersVisible(false)` hides
+  grid (and restores); `focusOn(1,0.5,0)` retargets OrbitControls to exactly [1,0.5,0];
+  `captureAudioStream()` returns a MediaStream with 1 audio track, release clean;
+  `POST /api/director` → `{version:1, keyframes:[], note:…}` and round-trips
+  `camPath.fromJSON` (0 keyframes, no throw); paths save→load→fromJSON reproduces 2
+  keyframes, DELETE → 200 then 404; `PATCH /api/anchors/1 {color}` → updated dict;
+  `GET /api/beats` → 404; `body.capsule` hides #annot-panel/#btn-path-save/#btn-path-del.
+
+**Blockers / questions for coordinator:** none. One conscious deviation, self-adjudicated
+(coordinator == foundation2 agent this round): paths route bodies implemented here instead
+of stub-marked for lane G — they were one-line calls into the db helpers I had to write
+anyway; stubbing them would have been more code than implementing. Lane G scope shrinks to
+capsule + pathsStore.js + deepening test_paths.py.
+
+**Next:** merge to `main`, then lanes E, G, F in parallel (each in its own worktree —
+directive 3 is mandatory for 5b).