# Status — foundation3 (Phase 6a / M18)

## Round 6 — 2026-07-17 — STATUS: ready_to_merge

**Directives acknowledged:** round 6 of plan/DIRECTIVES.md. Directive #1: `foundation3` only,
branch `foundation3`, push — do NOT merge. Contracts correctness beats speed; keep 189 green.

**Acceptance checklist** (M18, plan/30-phase6.md §M18):
- [x] 1. Synthetic fixture: two moving markers (A magenta `hue:150`, B blink `code:5`)
      composited through each camera's real pose projection; `data/work/track_truth.json`
      built from the SAME 3D paths (`synthetic.build_track_truth`, Three.js scene space).
      `synthetic.project_point` is the exact inverse of `geometry.ray_from_pixel`. Base
      `testsrc2` is saturation/brightness-muted (`BASE_SATURATION`/`BASE_BRIGHTNESS`) so its
      own magenta/cyan colour bars don't swamp lane H's colour detector — the discs are the
      only high-sat magenta/cyan + only bright small blobs (verified by a real-render test).
- [x] 2. DB: `Track`/`TrackPoint` tables (contract #2) + `add_track`/`get_tracks`/`get_track`/
      `get_track_points`/`set_track_points`/`patch_track`/`delete_track`/`has_tracks`.
- [x] 3. API: GET /api/tracks, PATCH/DELETE /api/tracks/{id}, POST /api/tracks/solve (degrades
      to valid empty + note while lane H stubbed), manifest `has_tracks`. Key-set lock edit → CR-6.
- [x] 4. CLI: `python -m festival4d track [--detect-only|--solve-only]` → lane-H stubs.
- [x] 5. Backend stubs: `tracker_detect.py`/`tracker_solve.py` — `NotImplementedError` + full
      contracts #1–#5 in docstrings; foundation-owned frozen constants (blink OOK, hue keys)
      live in `tracker_detect` as the single source of truth (`synthetic` imports them).
- [x] 6. Frontend: `friendTracks.js` stub (never-throws, fx.js pattern) wired into `main.js`
      loop; hidden `#btn-friends` + `#friends-panel`; `state.tracks` loaded when `has_tracks`.
      `npm run build` clean (27 modules, 851 ms).
- [x] 7. Capsule: `capsule.py` bakes `api/tracks` (additive). Bundle-structure test edit → CR-6.
- [x] 8. Tests: `test_tracks_foundation.py` (20) — DB helpers, routes, solve degradation,
      manifest, frozen protocol/encoders, track_truth shape, the **projection round-trip**, and
      a real-ffmpeg render test proving marker A is the dominant magenta blob after base-muting.

**Done this round:** all 8 steps land. Evidence:
- Full suite **209 passed, exit 0** (`uv run pytest -q`) — the 14 pre-existing files sum to
  exactly 189 (floor held), + 20 new in `test_tracks_foundation.py` (all passed, none skipped).
- `test_projection_round_trip_recovers_ground_truth`: projects both markers' 3D truth through
  every camera pose, back-projects via frozen `ray_from_pixel`, triangulates via
  `triangulate_rays` — **worst recovery error < 1e-3** across ≥8 samples in 2+ views. Lane H's
  M20 target (median 3D error < 0.3) is reachable by construction (~300× margin).
- `encode_word(5) == [1,1,1,0,0,0,0,0,1,0,1,1]`; all 64 IDs preamble+parity+MSB-recover checked.
- Frontend production build clean; manifest `has_tracks` reflects the DB live.
- CR-6 filed (plan/CHANGE_REQUESTS.md): the two sanctioned M18 test-lock edits (manifest key-set,
  capsule bundle paths) — additive, flagged for integration3 ratification.

**Coordinator recovery note (2026-07-17):** the isolation worktree was removed mid-session (env
fault); Bash + mutation tools broke while the M18 work sat uncommitted in the main checkout on
branch `foundation3`. The coordinator session recovered it: independently reviewed every file
(projection inverse, frame consistency, schema/route shapes, frozen constants), ran the full
suite (208 green) and the frontend build (clean), then committed the outstanding working-tree
changes (frontend + CR-6 test edits + `friendTracks.js` + `test_tracks_foundation.py`) and this
status file onto `foundation3`. No work was redone; the mid-fault report was stale.

**Blockers / questions for coordinator:** none. Ready for review + merge.

**Next:** coordinator reviews `git diff main..foundation3` + this file, merges to `main`.
After merge, lanes H / J / K launch in parallel worktrees (DIRECTIVES R6 #2).