Evict expired turn claims and stabilize turn listing order

[TheGreatAxios]

Summary

Expired in-memory turn claims no longer linger in the Map until that workbench is claimed again. tryClaim, holds, and release delete an expired entry when they observe it. A mismatched release still cannot evict a live successor (CL-7129), but it does drop a dead expired entry instead of leaving a zombie.

Turn listing and the running-turn resolver now share the same newest-first key: startedAt descending, with occurrence as the deterministic tiebreak. Same-millisecond timestamps no longer let listing keep Map insertion order while findRunningTurn picked a different row. The Drizzle store uses the same ORDER BY started_at DESC, occurrence DESC.

Test plan

• bun test packages/chat/src/turn-claims.test.ts packages/chat/src/agent-turns.test.ts packages/chat/src/turn-queue.test.ts — 47 pass, 0 fail (exit 0). New tests failed before the implementation (expired entry still releasable by the original token; listing order [first, second] vs running-turn second) and passed after.
• bun run typecheck — exit 0.
• bun run lint — prettier clean; eslint 0 errors / 10 pre-existing warnings.
• bun run check:structural — ok (deletion, killdates, licenses, db-gate, and remaining structural checks).
• Full bun run check reached the test step and failed in scripts/db-setup.test.ts with PostgresError: password authentication failed for user "thegreataxios" (pre-existing local DATABASE_URL, unrelated). Drizzle chat suites fail the same way.

CL-7200

Fixes CL-7200

[TheGreatAxios]

Fixes CL-7200

[TheGreatAxios]

Self-review

Verdict: the change is correct and narrowly scoped — expired turn-claim entries are now evicted as a side effect of liveHolder in tryClaim/release/holds, and listTurns/findRunningTurn (both in-memory and Drizzle stores) now share one newest-first comparator (startedAt desc, occurrence desc tiebreak). No further fixes needed.

• Zombie expired-claim eviction in turn-claims.ts (liveHolder): CONFIRMED-FIXED already in the PR — verified tryClaim, release, and holds all route through liveHolder, and the new tests prove eviction happens even on a mismatched-token release.
• Shared compareTurnsNewestFirst in agent-turns.ts, applied to both listTurns and findRunningTurn, and mirrored in the Drizzle ORDER BY started_at DESC, occurrence DESC: CONFIRMED-FIXED already in the PR — in-memory and DB orderings now agree with each other on same-millisecond ties.
• exactOptionalPropertyTypes hazards, bare catch {}, as T on untrusted input, fallbacks/legacy paths, product rules in apps/*: DISMISSED — none present in this diff; no catches, no casts, no optional-field assignment added.
• Doc comments (release/holds JSDoc, compareTurnsNewestFirst): DISMISSED — explain the non-obvious "why" (incidental cleanup vs. a caller's own claim), not restatements of the code.

Targeted tests: bun test packages/chat/src/turn-claims.test.ts packages/chat/src/agent-turns.test.ts packages/chat/src/turn-queue.test.ts — 47 pass, 0 fail. bun run typecheck — pass.

No commits pushed; nothing to fix.

[linear-code]

CL-7200