mokosh/.planning/phases/01-stabilize-video-pipeline/01-07-SUMMARY.md

phase: 01-stabilize-video-pipeline plan: 07 subsystem: video tags: [webm, vp9, mediarecorder, getdisplaymedia, offscreen, ffprobe, ffmpeg, mv3, chrome-extension, ring-buffer, restart-segments] # Dependency graph requires: - phase: 01-stabilize-video-pipeline provides: Plans 01..06 — doc cascade (D-A1..D-A6), Wave-0 test infra (vitest + 4 RED tests), offscreen recorder TDD (D-09..D-11 originally, D-13 after fix-a3), port keepalive + OFFSCREEN_READY handshake, SW shrink (alarms/IDB/tabCapture deletion + port host), build pipeline collapse (vite.config.ts inline plugin deletion) provides: - D-12 ffprobe acceptance gate (structural validation of tests/fixtures/last_30sec.webm) — exit 0, zero stderr - A3 empirical-playback acceptance gate (operator-confirmed Chrome playback + ffmpeg decoder dry-run exit 0, zero packet errors) - tests/fixtures/last_30sec.webm regression fixture (1.6 MB VP9 1142×1038 captured against the D-13 restart-segments recorder) - REQ-video-ring-buffer marked Complete; SPEC §10 acceptance criteria #2, #3, #7 functionally green at Phase 1 level - D-09..D-11 RETIRED in favor of D-13 restart-segments (mid-phase architectural correction, both pre-staged fallbacks activated) - CON-webm-header-retention RETIRED (D-13's per-segment header isolation makes it meaningless) affects: - Phase 2 (DOM + event-capture privacy) — capture pipeline is now always-on regardless of active tab; Phase 2 content scripts MUST NOT add competing keepalives (port 'video-keepalive' keeps SW alive) - Phase 3 (export pipeline + popup state machine) — popup will consume getSegments() output via the existing SW port host - Phase 4 (SPEC §10 smoke verification) — Phase 4 verifies the full 9-criterion sweep; Phase 1 only proved #2/#3/#7 - Phase 5 (P1/P2 hardening) — new entry: getDisplayMedia cursor visibility constraint (video: { cursor: 'always' }) - GSD framework retro candidate — auto-injection of empirical-acceptance gates when RESEARCH.md flags HIGH-risk assumptions # Tech tracking tech-stack: added: [ffprobe + ffmpeg (system CLIs used for the D-12 / A3 gates)] patterns: - "Pre-staged contingency activation: when RESEARCH.md flags an assumption as HIGH-risk, plan-time pre-stages a fallback skeleton (D-13 commented block in recorder.ts; base64 wire-format research in CONTEXT.md Doc Cascade). The smoke step then acts as an A/B gate: if simple-approach fails empirically, the executor activates the pre-staged fallback in-cycle rather than scheduling a new plan." - "Three-attempt acceptance pattern: attempt 1 (single-continuous recorder) failed at binary-transfer layer → D-12 fix; attempt 2 (after D-12) passed ffprobe but failed Chrome playback → A3 fix via D-13 activation; attempt 3 clean. Each failure was contained by its pre-staged fallback." key-files: created: - "tests/fixtures/last_30sec.webm — 1.6 MB regression fixture against the D-13 recorder (replaces stale fixture from 87909d9)" - ".planning/phases/01-stabilize-video-pipeline/01-07-SUMMARY.md — this file" - ".planning/debug/resolved/d12-blob-port-transfer-fails.md — D-12 debug session, resolved" - ".planning/debug/resolved/webm-playback-freeze.md — A3 debug session, resolved" modified: - ".planning/REQUIREMENTS.md — REQ-video-ring-buffer marked Complete; description AMENDED to reflect D-13 restart-segments" - ".planning/ROADMAP.md — Phase 1 row Complete; Success Criteria checked off; cursor-visibility refinement appended to Phase 5" - ".planning/STATE.md — Phase 1 closure block + frontmatter flip to phase_complete + Decisions log appended" key-decisions: - "D-12 acceptance gate (ffprobe) and A3 empirical-playback gate (operator + ffmpeg dry-run) treated as TWO distinct gates. The original Plan 07 conflated them under 'ffprobe-clean'; the A3 debug session proved they are independent. Phase 1 closure required BOTH green." - "Plan 07 closure is auto-handled (Task 2 of original PLAN.md) — the checkpoint:human-verify returned approved; the auto-closure flips REQ-video-ring-buffer + STATE + ROADMAP in one atomic commit and writes this SUMMARY in another." - "D-09..D-11 retirement is permanent. The original D-13 'fallback if D-12 fails' framing now stands as the production approach; CONTEXT.md decisions remain on record for SPEC provenance but the executable surface is restart-segments." - "Cursor visibility (video: { cursor: 'always' }) deferred to Phase 5, not back-patched into Phase 1. Phase 1 was a stabilization phase, not a UX-refinement phase; adding the constraint mid-closure would have widened the diff beyond the closure ceremony." - "Phase 1 closure satisfies SPEC §10 #2, #3, #7 functionally — but the canonical §10 sweep is owned by Phase 4. This avoids confusing 'Phase 1 closed' with 'SPEC §10 complete'; the latter requires the full 9-criterion smoke under Phase 4." patterns-established: - "Multi-EBML-header WebM concatenation is acceptable for the SPEC §10 #7 'plays back in a browser' criterion. Chrome's MSE pipeline handles it natively. The ffmpeg -f null decode dry-run produces muxer DTS-monotonicity warnings at segment join boundaries; these are NOT decoder errors and are documented as an expected D-13 trade-off — not a failure." - "Auto-closure of a checkpoint-gated plan: when a checkpoint:human-verify returns approved, a follow-up automation task (Task 2 of the same plan) lands the closure side-effects (REQ flip, STATE update, ROADMAP update, SUMMARY write). This pattern keeps the checkpoint task minimal and the closure ceremony atomic." - "Pre-staged fallbacks pay for their planning cost in the smoke step. Two-out-of-two HIGH-risk-flagged assumptions in Phase 1 (binary-transfer wire format under MV3 port serialization + VP9 keyframe orphan-P-frame risk under age-trim) failed empirically as predicted and were resolved by their pre-staged fallbacks without re-planning." requirements-completed: [REQ-video-ring-buffer] # Metrics duration: "~10min (Plan 07 closure ceremony); not counting the two debug sessions (~30 min D-12, ~45 min A3) which are accounted for in their respective resolved-session files" completed: 2026-05-15

Phase 1 Plan 07: Manual Smoke + ffprobe + Empirical Playback Acceptance Gates Summary

Two-gate phase closure (D-12 ffprobe structural + A3 empirical Chrome playback) green against tests/fixtures/last_30sec.webm after a three-attempt journey through two pre-staged fallback activations; REQ-video-ring-buffer complete, Phase 1 closed.

Performance

• Duration: ~10 min (closure ceremony only — three atomic commits + SUMMARY write). Plan 07's total elapsed time across all three smoke attempts was ~3.5 hours including the two debug sessions (D-12 ~30 min + A3 ~45 min); those are accounted for in the respective .planning/debug/resolved/*.md files.
• Started: 2026-05-15T21:40:00Z (this closure session, after operator returned approved on the checkpoint:human-verify)
• Completed: 2026-05-15T21:43:00Z (approx — three closure commits landed sequentially)
• Tasks: 2 (Task 1 = checkpoint:human-verify → operator returned approved; Task 2 = AUTOMATED closure with REQ flip + STATE update + SUMMARY)
• Files modified: 4 (fixture + REQUIREMENTS.md + ROADMAP.md + STATE.md) plus this SUMMARY created

Accomplishments

• D-12 ffprobe gate GREEN. ffprobe -v error -f matroska -i tests/fixtures/last_30sec.webm returns exit 0 with empty stderr. ffprobe -show_streams confirms valid VP9 codec, Profile 0, 1142×1038 frame, time_base 1/1000, start_pts 0, color space bt709.
• A3 empirical-playback gate GREEN. Operator confirmed end-to-end Chrome playback clean — no ~1 s freeze. ffmpeg -v warning -i tests/fixtures/last_30sec.webm -f null - exits 0 with zero decoder errors; the only warnings are muxer DTS-monotonicity reports at segment join boundaries (expected: D-13 concatenates three self-contained multi-EBML-header WebMs; Chrome's MSE pipeline handles this natively, satisfying SPEC §10 #7 "plays back in a browser").
• All 30/30 unit tests green across 8 test files (tests/offscreen/{codec-check,handshake,port,port-serialization,ring-buffer,segment-keyframes,segment-rotation,webm-playback}.test.ts). Both empirical ffmpeg dry-runs in webm-playback.test.ts flipped GREEN after the fresh fixture committed in cd61cbc — previously RED against the stale 87909d9 fixture.
• npx tsc --noEmit clean at closure time; npm run build clean (verified during the fix-a3 cycle, unchanged since).
• REQ-video-ring-buffer marked Complete in REQUIREMENTS.md (checkbox + traceability table row); ROADMAP Phase 1 row marked Complete 2026-05-15.
• D-09..D-11 retired permanently in favor of D-13 restart-segments; CON-webm-header-retention also retired. Captured in REQUIREMENTS.md amendment + STATE.md Decisions log.
• Cursor-visibility refinement deferred to Phase 5 — added to the P1/P2 hardening list with the explicit user-observation citation (2026-05-15).

Task Commits

Plan 07 closure ceremony (this SUMMARY's three atomic commits):

1. Task 1.5 (post-checkpoint): Fixture regeneration commit — cd61cbc (test): replaced the stale 87909d9 fixture with the fresh D-13-recorder capture (1.6 MB VP9 1142×1038).
2. Task 2a: Phase 1 closure flips — 7df72aa (feat): REQUIREMENTS.md REQ-video-ring-buffer flipped to Complete; ROADMAP.md Phase 1 row Complete + Success Criteria checked off + Phase 5 cursor-visibility appended; STATE.md Phase 1 Closure Notes block added + frontmatter to phase_complete + Decisions log entry.
3. Task 2b: SUMMARY write — <commit-3-hash> (docs): this SUMMARY committed.

Plan 07 also retained two prior debug-session arbitration cycles (already on the branch — they ARE the substance of Plan 07's execution, but each was committed as its own resolved-session bundle, not as Plan 07 commits per se):

• D-12 fix cycle (5 commits): c0d9166, d653283, 2831849, d5bb948, bf07619 — base64 wire-format binary transport.
• A3 fix cycle (6 commits): 5530292, 6a1a034, 670daa3, f81438d, 87909d9, 872f25d — D-13 restart-segments activation.

Note: Plan 07's original spec called for ONE commit at Task 2 completion. The closure ceremony was split into three atomic commits (fixture / REQ-STATE-ROADMAP flip / SUMMARY) so the SUMMARY can cite the prior commits by hash and so the REQUIREMENTS/ROADMAP/STATE flip is reviewable independently of the SUMMARY's narrative.

Files Created/Modified

Created (this closure session):

• tests/fixtures/last_30sec.webm — replaces the stale 87909d9 fixture; 1.6 MB; VP9 1142×1038; captured against the D-13 restart-segments recorder; concat of 3 × ~10 s self-contained WebM segments
• .planning/phases/01-stabilize-video-pipeline/01-07-SUMMARY.md — this file

Modified (this closure session):

• .planning/REQUIREMENTS.md — REQ-video-ring-buffer checkbox + description AMENDED + traceability row flipped to Complete
• .planning/ROADMAP.md — Phase 1 list-item + Success Criteria + Plan 07 row + Progress table row all flipped to Complete with 2026-05-15 date; Phase 5 P1/P2 list appended with getDisplayMedia cursor visibility refinement
• .planning/STATE.md — frontmatter status to phase_complete, completed_phases 0→1, completed_plans 6→7, percent 86→100; stopped_at + last_activity rewritten; Current Position rewritten for Phase 2 readiness; Performance Metrics Phase 1 row populated + Plan 07 row added; Decisions log appended with [Phase 01-07-closure] + [Phase 01-07-deferred-to-5]; Session Continuity rewritten; Phase 1 Closure Notes section added

Created in prior fix cycles (referenced for context, not in this closure):

• src/shared/binary.ts — D-12 fix: portable Blob ↔ base64 helpers
• tests/offscreen/port-serialization.test.ts — D-12 fix: 6 tests proving JSON serialization corruption + base64 round-trip pin
• tests/offscreen/segment-keyframes.test.ts — A3 fix: production-driven RED block (now GREEN) + documentation + GREEN-pinning blocks
• tests/offscreen/segment-rotation.test.ts — A3 fix: 8 tests pinning D-13 ring-buffer invariants
• tests/offscreen/webm-playback.test.ts — A3 fix: 2 empirical ffmpeg dry-runs (RED until fresh fixture, GREEN after cd61cbc)
• .planning/debug/resolved/d12-blob-port-transfer-fails.md
• .planning/debug/resolved/webm-playback-freeze.md

Modified in prior fix cycles:

• src/shared/types.ts — D-12: added TransferredVideoChunk; A3: renamed → TransferredVideoSegment + field renames + isFirst dropped
• src/offscreen/recorder.ts — D-12: base64 encode side; A3: D-13 restart-segments activation (the main rewrite, replacing D-09..D-11)
• src/background/index.ts — D-12: base64 decode side; A3: segment-semantics adaptation + mergeVideoSegments
• tests/offscreen/ring-buffer.test.ts — A3: retired to a vestigial breadcrumb after segment-rotation supersedes it

Decisions Made

1. Plan 07 closure is split into three atomic commits. The original spec called for one commit at Task 2 completion. Splitting (fixture / REQ+STATE+ROADMAP flip / SUMMARY) makes each commit reviewable in isolation and lets the SUMMARY cite the fixture and closure commits by hash. Trade-off: three commits where one was specced — judged a worthwhile diff-clarity improvement.
2. D-12 + A3 are treated as TWO distinct gates. The original PLAN.md framed acceptance as "ffprobe-clean" (a single gate). The A3 debug session proved that a ffprobe-clean file can still freeze in Chrome playback — they are independent. Phase 1 closure requires both green, and the SUMMARY documents both gates explicitly so future phases can't conflate them.
3. D-09..D-11 retirement is permanent. The original D-13 framing in CONTEXT.md was "fallback if D-12 fails." After A3 activated it, D-13 IS the production approach. CONTEXT.md retains D-09..D-11 for SPEC provenance, but REQUIREMENTS.md, ROADMAP.md, and the executable surface (src/offscreen/recorder.ts) all reflect D-13 as authoritative.
4. The muxer DTS-monotonicity warnings are NOT a failure. ffmpeg -f null - prints warnings at segment join boundaries because the three concatenated WebM segments have overlapping per-segment timestamps (each segment's pts restarts at ~0 in its own EBML segment). This is the documented D-13 trade-off for multi-EBML-header WebM concat. SPEC §10 #7 only requires "plays back in a browser" — Chrome's acceptance is sufficient and was operator-confirmed.
5. Cursor visibility refinement deferred to Phase 5, not back-patched into Phase 1. Phase 1 is a stabilization phase; adding the cursor: 'always' constraint mid-closure widens the diff beyond the closure ceremony. Phase 5 is the right home for capture-quality refinements.

Deviations from Plan

Deviations from the ORIGINAL Plan 07 spec

1. [Rule 4 → architectural escalation, then auto-resolved] D-12 binary transfer failure surfaced during first smoke attempt

• Found during: Task 1 first attempt (operator's first ./smoke.sh run)
• Issue: Saved last_30sec.webm was 75 bytes of literal "[object Object]" text — chrome.runtime.Port JSON-serializes payloads across extension contexts, corrupting Blob → {} → "[object Object]" in the SW-side Blob ctor
• Fix: Pre-staged fallback activated — added src/shared/binary.ts with portable Blob ↔ base64 helpers; encoded on the offscreen side (REQUEST_BUFFER handler), decoded on the SW side (BUFFER receive)
• Files modified: src/shared/binary.ts (new), src/shared/types.ts, src/offscreen/recorder.ts, src/background/index.ts
• Verification: 6 new tests in port-serialization.test.ts (including a byte-exact reproduction of the 75-byte payload + a GREEN-pinning block for the base64 wire format); empirical re-smoke after fix produced a 2.1 MB ffprobe-valid WebM
• Committed in: c0d9166, d653283, 2831849, d5bb948, bf07619
• Resolved-session doc: .planning/debug/resolved/d12-blob-port-transfer-fails.md

2. [Rule 4 → architectural escalation, then auto-resolved] A3 cluster-alignment freeze surfaced during second smoke attempt

• Found during: Task 1 second attempt (operator's re-smoke after D-12 fix landed)
• Issue: The ffprobe-valid WebM froze ~1 s into Chrome playback. ffmpeg -v warning -i ... -f null - showed 8× Error submitting packet to decoder: Invalid data found + File ended prematurely at pos. 2100851. Root cause: D-09..D-11's age-trim evicted middle chunks containing VP9 keyframes that subsequent retained tail chunks depended on (orphan P-frames)
• Fix: Pre-staged fallback activated — the D-13 restart-segments skeleton commented at the bottom of src/offscreen/recorder.ts (lines 298-316 originally) was activated. Recorder lifecycle replaced: stop()/start() every 10 s on the same MediaStream, keep last 3 self-contained ~10 s WebM segments (3 × 10 s = 30 s preserved). Each segment is independently decodable. As a side effect, per-segment .stop() also fixed the "File ended prematurely" Matroska finalization gap
• Files modified: src/offscreen/recorder.ts (rewrite), src/background/index.ts (segment semantics + mergeVideoSegments), src/shared/types.ts (TransferredVideoChunk → TransferredVideoSegment + field renames + isFirst dropped), tests/offscreen/ring-buffer.test.ts (retired), tests/offscreen/segment-rotation.test.ts (new)
• Verification: 28/30 tests green immediately after the fix; the 2 remaining REDs were the empirical ffmpeg dry-runs against the still-stale fixture, which flipped GREEN once the fresh fixture committed in cd61cbc; operator-confirmed end-to-end Chrome playback clean
• Committed in: 5530292, 6a1a034, 670daa3, f81438d, 87909d9, 872f25d
• Resolved-session doc: .planning/debug/resolved/webm-playback-freeze.md

3. [Closure ceremony split into 3 commits, not 1] See Decisions Made #1 above.

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Total deviations: 2 architectural escalations (both pre-staged fallback activations), 1 closure-ceremony commit-split. Both architectural escalations were anticipated in CONTEXT.md and RESEARCH.md (HIGH-risk flags); both pre-staged fallbacks activated cleanly without needing a fresh phase plan. The commit-split was a Plan 07 spec deviation but improves reviewability.

Impact on plan: The two pre-staged fallbacks paid for their planning cost in the smoke step exactly as designed. Phase 1's overall structure held; no plan re-numbering was needed; no /gsd-insert-phase was called. The closure ceremony itself is on-spec modulo the 3-commit split.

Issues Encountered

Three smoke attempts, two pre-staged fallback activations, one clean acceptance.

Attempt 1 (single-continuous MediaRecorder, originally specced under D-09..D-11):

• Result: 75-byte text file in the archive (5 × "[object Object]")
• Root cause: D-12 — chrome.runtime.Port JSON-serializes payloads, corrupting Blobs
• Resolution: Activate the base64 wire-format pre-stage from CONTEXT.md Doc Cascade

Attempt 2 (D-12 fix landed, single-continuous recorder retained):

• Result: 2.1 MB ffprobe-valid WebM; opens in Chrome but freezes ~1 s in
• Root cause: A3 — VP9 keyframe orphan-P-frame issue under age-trim eviction of middle chunks
• Resolution: Activate the D-13 restart-segments pre-stage from CONTEXT.md

Attempt 3 (D-12 + A3 fixes both landed, D-13 recorder):

• Result: 1.6 MB WebM (3 × ~10 s self-contained segments concatenated); ffprobe exit 0; ffmpeg dry-run exit 0 with zero decoder errors; operator-confirmed clean Chrome playback end-to-end
• Resolution: Commit the fresh fixture as tests/fixtures/last_30sec.webm; close Phase 1

Process Observation — Candidate for GSD Framework Retro

Plan 01-07's smoke step ended up surfacing TWO unanticipated-cascade failures (D-12 binary transfer + A3 keyframe alignment), each of which had a pre-staged fallback that activated cleanly without needing a fresh phase or replan.

This is a real datapoint for the GSD framework. Two observations:

1. Pre-staging works. RESEARCH.md flagged both binary-transfer semantics under MV3 port serialization AND VP9 keyframe orphan-P-frame risk under age-trim as HIGH-risk assumptions. CONTEXT.md and PLAN.md pre-staged fallbacks for both (the Doc Cascade for binary transfer; the D-13 commented skeleton for keyframe alignment). Both HIGH-risk assumptions failed empirically, exactly as flagged. Both pre-staged fallbacks activated within ~30-45 min of detection. No re-planning was required.

2. Plan 07's smoke step DID the empirical-acceptance-gate work that was, in spirit, what RESEARCH.md was warning about. The smoke step is supposed to be a confirmation gate; it ended up being a discovery gate twice in a row.

Candidate retro question for /gsd-plan-phase: When RESEARCH.md flags an assumption as HIGH-risk AND a fallback is pre-staged, should the planner automatically inject an empirical-acceptance gate (e.g. ffmpeg dry-run + Chrome playback for video/codec assumptions; cross-context message round-trip test for MV3 messaging assumptions) BEFORE the phase's final commit-merge, rather than discovering the failure during the human-verify smoke step? The current sequence (Plan 01 → ... → 07 = smoke → debug session if smoke fails) works, but a slightly tighter feedback loop ("if smoke would surface a HIGH-risk-flagged failure, escalate to the pre-staged fallback BEFORE creating a debug session") might shorten the orchestration overhead in future phases that have similarly cascade-prone subject matter (codec / wire-format / container-spec work in particular).

Not a process bug — a possible process refinement. Logged here for /gsd-plan-phase retro consideration in Phase 2 or beyond.

This is the SECOND debug session in Phase 1's life — both written up in .planning/debug/resolved/. The cycle latency between "manual smoke reveals the issue" and "RED test in place + fix landed" was ~30 minutes for D-12 and ~45 minutes for A3. Acceptable but worth tightening.

User Setup Required

None — Phase 1 ships as a Chrome extension with desktopCapture permission; the operator interacts with chrome://extensions "Load unpacked" for development and Chrome's native screen-share picker for capture. No external services configured by Phase 1.

The cursor visibility refinement (Phase 5) will, when activated, add a cursor: 'always' constraint to the getDisplayMedia call in src/offscreen/recorder.ts — no user action required there either, just a one-line code change in Phase 5.

Next Phase Readiness

Ready for Phase 2: The offscreen now owns capture entirely. Phase 2 (DOM + event-capture privacy via rrweb v2 maskInputFn + content-script input logging) plugs into the existing content-script architecture and does NOT touch the offscreen.

Constraints Phase 2 must respect:

• The port 'video-keepalive' keeps the SW alive. Phase 2's content-script work MUST NOT add competing keepalives (e.g., redundant chrome.alarms, redundant ports). Audit P1 #8 (alarms keepalive ineffective) was resolved in Phase 1 by deleting chrome.alarms; do not re-introduce it.
• The SW's onMessage listener validates sender.id === chrome.runtime.id (T-1-04 SW-side sender check, documented 4 places in src/offscreen/recorder.ts). Content scripts have the same extension ID and pass this check. If Phase 2 adds a new sender path (e.g., an injected page-world script via chrome.scripting), Phase 2 must respect the guard.
• mergeVideoSegments in src/background/index.ts IS the export path for video. Phase 2 work goes into events.json / session.json; no merge function changes needed.

Workflow next steps (per user settings: deep code-review + verifier enabled):

1. /gsd-code-review (deep code-review gate on the Phase 1 branch) — covers all 25-ish Phase 1 commits including the two debug-session fix cycles + this closure ceremony.
2. /gsd-verify-work (verifier — runs the full vitest + tsc + grep gates against the Phase 1 branch).
3. After both pass: merge Phase 1, plan Phase 2 via /gsd-plan-phase 2.

Blockers / concerns: None. Phase 1 is complete; the two debug sessions are documented and resolved; pre-staged fallbacks worked as designed.

Self-Check: PASSED

Verified after writing this SUMMARY:

• tests/fixtures/last_30sec.webm exists (1 633 459 bytes) ✓
• .planning/phases/01-stabilize-video-pipeline/01-07-SUMMARY.md exists (this file) ✓
• Commit cd61cbc (fixture replacement) in git log --all ✓
• Commit 7df72aa (closure flips) in git log --all ✓
• grep -c "Phase 1 closure" .planning/STATE.md → 3 (≥ 1) ✓
• grep "REQ-video-ring-buffer" .planning/REQUIREMENTS.md shows [x] ✓
• grep "Complete" .planning/ROADMAP.md shows Phase 1 row Complete 2026-05-15 ✓
• npx vitest run → 30/30 green ✓
• npx tsc --noEmit → exit 0 ✓
• ffprobe + ffmpeg dry-run both exit 0 ✓

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Phase: 01-stabilize-video-pipeline Completed: 2026-05-15