Task: Integrate Design video preparation into main

Identity

Integrate the completed Design video preparation source 1acca836fe into local main and reconcile its accepted Design contracts. Own only this integration record and relevant canonical Design memory; imported source records remain unchanged.

User explicitly authorized releasing old task 20260915-merge-image-preview-56ab481e, adopting this root while preserving its 3 known foreign documents, and releasing this integration ownership after completion. No push, deployment, paid generation or worktree deletion is authorized.
Concurrent and Planning Gates passed: exclusive integration ownership matches this root/branch/base; entry, source outcomes, Design ADR, domain, architecture and relevant evidence/commitment context were loaded. Historical peer records remain read-only; placeholder scopes are unknown and are not integration sources.
Preserve Current Specification authority, immutable revision-bound Quote and explicit confirmation. Preparation does not create chat Turns or paid media Tasks. Source and client/server counterparts must be released together.
Preserved foreign paths: .project-docs/30-worklog/tasks/20260901-package-122-c5e8.md, .project-docs/30-worklog/tasks/20260901-package-123-d7f3.md, .project-docs/30-worklog/tasks/20260902-client-hang-diagnosis-a47c9e2b.md. Their original bytes and index state are retained; never stage them.

Fast-forwarded local main from b723c7220b to exact source 1acca836fe035dd462110cdc7683645c1e031f54; no merge conflict or product rewrite. Source task record imported unchanged from its retained branch.
Promoted the user-approved preparation/capability/binding contract to the accepted Design ADR and domain rules and recorded source provenance in current-state. This clarifies the explicit video starting-image selection; it does not introduce another semantic authority or bypass confirmation.
The 3 known foreign dirty documents remain outside staging and are retained. User-authorized integration ownership release is performed only after final documentation/commit checks.

Root verification after fast-forward: five related unit files, 76 tests passed in 4.48s. pnpm run typecheck and pnpm run build:vite passed; Renderer/Main/Preload/utility targets built successfully. Existing Browserslist, mixed-import and chunk-size warnings remain. No installer packaging or Electron E2E run in this integration.
Paired main-branch verification: DESIGN_DIAGNOSTIC_SERVER points to the actual server master root; the client diagnostic passed 2 tests in 13.31s. Actual React/store preparation commands reach the real Python Workspace/compiler bridge, with zero blockers before quotation; the test then explicitly confirms. Separate backend lifecycle coverage proves persisted Task execution and ready Asset projection with provider/storage/ledger fixtures.
Tests do not establish real model quality, installed-app WebSocket transport, production staging/storage or MP4 decoding. No live model/provider, paid generation, push or deployment was performed.
check_project_docs, task-aware check_doc_drift and git diff --check passed. Product/index comparison against the exact source is empty; all 3 preserved foreign files match their pre-adoption bytes and none are staged. Source worktree is clean and its latest HEAD is now included in the local main branch.

After paired deployment, separately authorize a real short-video acceptance covering image staging, model output, ingestion and actual playback. Local fixture-backed tests do not prove production availability.
Source worktree cleanup offered with its full path/branch; awaiting confirmation. Retain its checkout, branch and commits unless separately approved. This does not hold up the completed merge.

Applied the completed source's accepted Design preparation proposal without changing unrelated product direction. Source task files remain read-only.