update sessions/0026/SESSION-0026.0-TRANSCRIPT-2026-06-27T15-26--INPROGRESS.md

sessions/0026/SESSION-0026.0-TRANSCRIPT-2026-06-27T15-26--INPROGRESS.md

@@ -14,10 +14,56 @@
 
 ## Launch prompt
 
-_(launch prompt not captured at claim time)_
+Build scrub-driven altitude transitions in the simulator, per the approved design at
+`docs/superpowers/specs/2026-06-27-scrub-driven-altitude-transitions-design.md`. Write the
+implementation plan from that spec, review it, then execute it. Make the Altitude knob
+position continuously drive the transition: dragging the dial scrubs the morph video's
+currentTime and crossfades the two adjacent scale soundtracks by knob angle; hold-partway
+(no auto-complete), fully reversible, re-roll the destination clip on each fresh approach,
+scroll-wheel auto-scrubs one altitude then locks, lock-per-altitude preserved. Phase 1:
+build against current morphs. Phase 2: re-bake all 154 morphs all-intra for smooth seeking,
+re-push via git-LFS. Unit tests for pure scrub logic + extend Playwright E2E.
+
+## Plan
+
+> Anchor: design docs/superpowers/specs/2026-06-27-scrub-driven-altitude-transitions-design.md (R2a — ELIGIBLE)
+> Session type: planning-and-executing (fused) — write the plan, then execute it, ship via §9.
+
+Scrub-driven altitude transitions. Continuous `pos` (float) drives morph `currentTime` +
+two-soundtrack audio crossfade by `frac(pos)`; integer crossing commits + locks + re-rolls.
+Phase 1 = interaction against current morphs; Phase 2 = all-intra re-bake (154 morphs, LFS).
+Pure scrub logic kept separable + unit-tested; Playwright E2E extended to assert currentTime
++ audio gains track the dial and reverse on turn-back.
+
+### Progress (checkpoint @ Phase-1 done)
+
+- Plan: `docs/superpowers/plans/2026-06-27-scrub-driven-altitude-transitions.md` (approved "execute as-is").
+- **Phase 1 DONE** (branch `session-0026`, 5 commits):
+  - T1 `simulator/static/scrub.js` (pure UMD math) + `simulator/unit/scrub.test.js` (9 `node --test`).
+  - T2 two-element audio crossfade (`<audio id=aud-b>`, `blendAudio`/`restAudio`/`ensurePlaying`/`assignElements`).
+  - T3 scrub engine: drag live-drives `pos`; `setPos` seeks morph currentTime (1 seek/rAF), crossfades audio,
+    commits+locks+re-rolls on integer crossings; release holds (no auto-complete); client-side `pickPoolClip`.
+  - T4 wheel + label-tap → `autoScrub` (animate `pos`, land exact, lock); removed dead `advance()`/`playTransition()`.
+  - T5 E2E scrub tier (6 tests green): drag tracks currentTime+gains, turn-back reverses same file + re-locks start,
+    detent-crossing commits+locks (via `window.__hefState` seam), wheel auto-scrubs+locks.
+- **Verification:** `node --test` 9 green · `pytest` 302 passed / 2 skipped · Playwright 6 green.
+- **Phase 2 NEXT:** re-bake 154 morphs all-intra (`-g 1`) in `build_pool_manifest.py` + LFS re-push (T7–T8),
+  then ship via §9 (PPE).
+- Operator by-eye "feel/smoothness" review still pending (no Chrome on box) — Phase 2 fixes scrub steppiness.
 
 ## Deferred decisions
 
 _Autonomous-mode low-confidence calls the driver made and would have
 liked operator input on. Appended as the session runs; surfaced at
 finalize. Empty if none._
+
+- **D1 (plan) — canonical segment morph file.** The spec's component 2 says resolve the
+  directed morph via `morphByPair["<fromClip>→<toClip>"]`, but its turn-back decision says
+  "scrubs the SAME morph in reverse" with full reversibility. These are only mutually
+  consistent if a segment uses ONE file scrubbed bidirectionally. I locked the plan to:
+  per segment `[lo, lo+1]`, always use the **descend/forward** morph
+  `morphByPair["<clip@lo>→<clip@lo+1>"]` and drive `currentTime = frac × duration` in both
+  travel directions; the `.rev` files become unused by the scrub interaction (kept baked
+  for back-compat). This means the old E2E "zoom-out plays a `.rev`" assertion is replaced
+  by a "turn-back seeks the same file backward" assertion. Low-confidence on whether the
+  operator specifically wanted `.rev` retained in the drag path.