fix(task-board): a repo-backed task reaches In Review only with a PR

[guitavano]

Follow-up to #5970, which shipped the repo task property but intentionally kept the plain thread-finish backstop (its refactor commit dropped the gate). That leaves a repo-backed task dead-ending In Review with no PR: it finished but opened no PR, so there's nothing to review.

The rule

A repo-backed task reaches In Review only when a PR exists:

• The agent's PR-open hook moves it mid-run (unchanged).
• On thread-finish, the backstop advances it only once a PR is linked — otherwise it stays In Progress (the CMS submit-for-review flow opens the PR later).
• Non-repo tasks advance on finish exactly as before.

Changes

• shouldAdvanceToReview gains a hasPr arg; a repo-named item stays In Progress on finish unless a PR is linked. Pure, unit-tested.
• Both callers — the thread-finish hook (advanceLinkedTasksToReviewOnThreadFinish) and the stall sweep (recoverStalledTasks) — compute hasPr via listPrs, querying only for repo-backed items (non-repo path stays query-free).

Testing

• Unit: repo-backed + no PR → stays; repo-backed + PR → advances; non-repo unchanged.
• Real-Postgres: a repo task holds In Progress on finish with no PR, then advances once a PR is linked.
• tsc clean (apps/api); 37 unit tests pass; lint clean.

🤖 Generated with Claude Code

---

Summary by cubic

Prevents repo-backed tasks from entering In Review without a PR. Previously, thread-finish could advance a repo-backed task to In Review with no PR; now it stays In Progress until a PR is linked. Non-repo tasks are unchanged, and the agent’s PR-open hook still moves tasks mid-run.

• shouldAdvanceToReview now accepts hasPr; repo-backed tasks require a linked PR to advance on finish.
• advanceLinkedTasksToReviewOnThreadFinish and recoverStalledTasks compute hasPr via listPrs only for repo-backed tasks (no added queries for non-repo).
• Tests cover: repo-backed + no PR → stays; repo-backed + PR → advances; non-repo unchanged; Postgres integration verifies hold-then-advance after linking a PR.

^{Written for commit 2eafa41. Summary will update on new commits.}