fix: free-plan deploy, seekable playback, and interview worker name

[mrevanzak]

Summary

• Deploy the finalizer without Cloudflare Containers (Workers Paid). Local alchemy dev still uses the ffmpeg image; remote deploy concatenates uploaded parts in the Worker.
• Make MediaRecorder WebM seekable by writing a Cues/Duration index on finalize and rebuilding a blob in the player, so the timeline can be scrubbed.
• Publish the public web Worker as interview (interview.mrevanzak.workers.dev).

D1 migration squash is already on main.

Commits

1. fix(finalizer): concat parts on free-plan deploy without Containers
2. fix(playback): make MediaRecorder WebM seekable
3. chore(infra): publish the web worker as interview

Test plan

• pnpm --filter @interview-web/finalizer test
• pnpm --filter web exec vitest run tests/recording-playback.test.ts tests/recording-playback-view.test.tsx
• bun run deploy succeeds on a free Cloudflare account
• Public URL is https://interview.mrevanzak.workers.dev
• Record a Chrome/Firefox take, open operator playback, scrub the timeline
• Existing published recordings become seekable after this web deploy (no re-record)

[access-time-code-pr-reviewer]

Review Summary

This PR adds recording playback, WebM processing, passthrough finalization, and expanded recording test coverage. However, it exposes recording submission deletion without authentication or authorization, allowing anyone with an enumerable session ID to delete stored recording data.

Key Changes:

• Adds recording playback UI and object URL preparation for WebM and other media.
• Adds WebM seekability and segment splitting support.
• Adds a passthrough finalizer for WebM recordings when ffmpeg is unavailable.
• Expands unit and end-to-end coverage for recording, playback, and finalization flows.
• Adds or exposes recording submission deletion without access control.

Confidence Score: 5/5

Recommendation: Request changes before merge.

Rationale: The unauthenticated destructive endpoint is a clear, directly evidenced security vulnerability, and the affected recording identifiers can be enumerated through the unauthenticated listing flow.

Special Attention

- Require operator authentication and authorization before mounting the submission DELETE endpoint. - Add CSRF protection if authorization relies on cookies. - Review authentication and authorization for recording list and playback access. - Verify internal finalization routes cannot be invoked or abused externally.

Important Files Changed

File	Overview
apps/web/src/routes/api/recordings/$sessionId/submission.ts	Handles recording submission access and deletion; its DELETE operation currently lacks authentication and authorization.
apps/web/src/recording/playback.ts	Builds recording submission URLs and loads recording bytes for playback.
apps/web/src/recording/playback-view.tsx	Renders the recording list and playback detail views.
packages/finalizer/src/domain/webm-seekable.ts	Parses and transforms WebM data to support seekable playback and recovered segments.
packages/finalizer/src/worker/passthrough.ts	Provides an in-memory WebM finalization path when the ffmpeg container is unavailable.

Flowchart

flowchart TD
  A[Caller obtains or enumerates session ID] --> B[Unauthenticated recording API]
  B --> C{Request method}
  C -->|GET| D[Read recording submission]
  C -->|DELETE| E[Delete stored parts and output]
  E --> F[Recording data lost]
  G[Required operator authorization] -.-> C

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Audit history

[access-time-code-pr-reviewer]

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_{🤖 review-bot · openai/gpt-5.6-luna · standard · 123.3s · 805,557 tokens · diff: 16 files · preloaded context: 17 changed + 8 related · 1 noise filtered · policy: github-pr-review, thermo-nuclear-code-quality-review · optional skills invoked: none}