Merged after reconciling the whole stack onto the tip, operator-reviewed before merge.
The core ownership fix for GHSA-wvxc-jp3v-5mg5 had already landed via #13211 with a different implementation of the same endpoint. This branch carries a stricter one, built up in layers: this PR, #13262 (explicit scope, audit log, atomic sweep), #13297 (revoked, deactivated, banned or expired keys rejected) and #13374 (owner-scoped file half, chunked instance sweep — SEC-C/SEC-D). The stack's implementation was kept over #13211's because it is stricter on every point:
- **route:** with #13211, a request carrying BOTH a dashboard session cookie and an API key swept the whole instance. Here a presented key always scopes the sweep to that key; only a session without a key sweeps all tenants; neither returns 401. Instance-wide and row-deleting sweeps log at warn as an audit trail, and a failing sweep returns a sanitized 500.
- **`deleteCompletedBatches`:** takes an explicit `{ apiKeyId } | { allTenants: true }`. An omitted or blank key throws instead of widening, and passing both throws.
- **files:** a key sweep only soft-deletes files the caller owns (`deleteFileOwnedBy`), so a batch referencing another tenant's or an unowned file never nulls its content.
- **transactions:** key mode is all-or-nothing across chunks; instance mode commits per 200-id chunk so a large sweep never holds one write lock on the table.
#13211's own test was aligned to the explicit-scope API with its assertions unchanged. Its seed now creates the file with the batch's owner, as an upload through that key does in production — without that, SEC-C correctly leaves the unowned file intact.
- 51/51 across the six batch suites (#13211's test, this stack's ownership and route-scope tests, `batch-deletion`, `batch-deletion-route-logic`, `files-delete-owned-by`)
- ESLint, `typecheck:core`, complexity, cognitive-complexity, changelog integrity: clean
⚠️ base-red inherited: #12732
Resynced onto the release tip after #12051/#12052/#12053 landed. Same LKGP-clear conflict as #12053 (kept the current clearStaleLKGP() helper at both call sites). One additional issue this final phase's combined-worktree validation surfaced: clearStaleLKGP() itself (added by #12013, which none of the 4 phase PRs could have seen since it landed after they were authored) still had a dynamic `await import("@/lib/localDb")` — a real break once this PR deletes the barrel. Fixed to `await import("@/lib/db/settings")`, matching the direct-import pattern used at every other call site. typecheck:core, check-db-rules, check:cycles, and the eslint-import-boundaries regression test (3/3, including "G14 rejects localDb barrel imports") all green after resync — zero barrel-importing production files remain. Nice clean 5-phase migration, and thanks for taking on the full #11795 cleanup.
