Bound original-library metadata reads and preserve upload errors

[Chris0Jeky]

Audio uploads rejected by the host now preserve the standard 413 response after transaction rollback instead of surfacing as a generic server error. Original-library pages authorize candidate boards, then retrieve up to twenty owner-scoped metadata rows in one detached SQL projection, avoiding per-entry capture graph reads and clipping evidence excerpts in SQL.

Continues #2808 and the recorded integration review follow-through. Stacked on #2870; preserve that base until it lands. No schema migration, frontend behavior, implicit model call or board mutation is introduced.

Verification

• dotnet test backend/Taskdeck.sln -c Release -m:1: 9,183 passed, 34 existing skips (Domain1639, Application4258, API3008, CLI243, Architecture28, Integration7).
• Nine focused ThinkingAudioApiTests pass. A partially read stream throws the host 413 exception and proves rollback leaves no blobs, references, capture, answer or model request. A real SQLite command interceptor verifies one query per nonempty library page, zero for an empty page, SQL excerpt clipping, exact ordering, owner exclusion and no tracked capture graphs.
• npx playwright test tests/e2e/original-audio-library.spec.ts --project=chromium --workers=1: passed against this backend and an isolated synthetic SQLite database; retained-source discovery, exact-byte playback/download, archival and the shared experience path remain functional.
• Doc links, GitHub operations governance and diff checks pass. Independent bounded Luna review: no HIGH/CRITICAL or additional MEDIUM query/privacy defect.

Initial compile errors (missing ErrorCodes import and ambiguous Capture type in the fixture) were corrected before these passing checks. Evidence is retained under C:/Taskdeck-overhaul/evidence/source-scalability-* and SOURCE-SCALABILITY-VALIDATION.md.

No production database or primary checkout changed. Direct Kestrel socket transport, physical microphone, automatic transcription, live provider, deployment and restore acceptance are not claimed. Indexed original-history cursors are the next separate continuation. The existing OUTSTANDING_TASKS.md owner decisions remain unchanged.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-09-10T01:51:48.502112Z	df83c1c	PR opened

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[Chris0Jeky]

Independent bounded Luna review of ac13824..df83c1c completed: no HIGH/CRITICAL or additional MEDIUM query/privacy defect. The host 413 rollback path and owner-scoped single-query projection retain the existing private-source authority. Root observed all9183backend tests passing (34existing skips),9focusedAPI cases and the real original-library browser journey. No provider/device/production acceptance is inferred.