[laneB] log: M2 session 2

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

logs/laneB.md

@@ -59,3 +59,47 @@ NEXT: Hold at M1 boundary. At SYNC 1 the stub swaps for the real Stage
   (one-line change in the page import) and tldev.html/stagestub.js get
   deleted. M2 (locked): clip crossfade polish, params/cut lane UI, snapping
   config, undo Ctrl+Z already stubbed, box-select multi-drag.
+
+## 2026-07-18 session 2 (M2)
+DONE: M2 per orchestrator update. SYNC findings fixed first, then polish.
+  - SYNC1 #3a/#3b: added `Timeline.onLoad(cb)`; `load()` fires it →
+    TimelineUI rebuilds rows + refreshes name/duration fields. Verified with
+    the exact repro (UI built against empty stage, then `load()` a 2-entity
+    scene → rows now appear, scene bar updates).
+  - SYNC1 #4 clipdrop: `scenegod:clipdrop {id,path,clipIndex}` → `addClipDrop`
+    drops a block at the playhead, `out = clip.duration` (from preload), auto
+    `fade:0.25` where it abuts a neighbour. Verified via dispatched event.
+  - Crossfade fade-IN (was fade-OUT only): a predecessor's fade pre-rolls the
+    successor's playback start earlier by `pred.fade` so local time is
+    continuous across the boundary; weights ramp 1→0 / 0→1 and sum to 1
+    (asserted in test).
+  - Params lanes (per-key hue), camera-cut lane add via dblclick on Cameras
+    row (uses active cam / first camera), snap toggle in scene bar (Alt still
+    = free), box-select + multi-drag + Delete of keys, selection highlight,
+    fade wedge drawn on clip blocks, panel grows to content height (was fixed
+    200px → clipped the Cameras row once params rows were added).
+  - timeline_test.mjs extended: onLoad fires once, addClipDrop out=duration,
+    crossfade weights sum to 1. All green.
+DECISIONS / BUG:
+  - **tlui reads tracks from the TIMELINE, not the stage entity.** Found mid-
+    verify: `load()` structuredClones the scene, so timeline.scene.entities and
+    stage entities are SEPARATE objects. Drawing from stage meant clipdrop/
+    addKey (which mutate the timeline copy) never appeared. Repointed all draw
+    methods to `_te(id) = tl.scene.entities.find(id)`. Rows now built from the
+    timeline list merged with any stage-only (dock-added, not-yet-keyframed)
+    entities. Per PLAN the timeline owns tracks — this is the correct source.
+  - Grow-to-content height, no scroll yet (ponytail: add max-height+scroll only
+    if a scene ever has enough entities to dominate the viewport).
+BLOCKED/REQUESTS:
+  - Gap for the orchestrator/Lane A to note: there's no bridge for a
+    dock-added stage entity to enter `timeline.scene.entities`, so a freshly
+    dropped character can't be keyframed until a scene load. tlui shows it as a
+    row (empty tracks) but mutators need the entity present. If Lane A's dock
+    should register new entities with the timeline, we need a
+    `timeline.addEntity(desc)` (or the dock calls `stage.captureState()` →
+    `timeline.load`). Flagging for SYNC 2 — not building it uninvited.
+  - Verified with a throwaway harness (`_check.html`) served on :8099; deleted,
+    NOT committed (orchestrator removed the M1 tldev.html deliberately).
+NEXT: Hold at M2. Remaining M2 polish if a session 3 is granted: undo already
+  wired to Ctrl+Z; could add snapping increment config + keyable-param add UI
+  (currently params keys come from Lane A capture/inspector). Await SYNC 2.