Greptile Summary

This PR introduces a task-executor facade layer that routes ACP task lifecycle writes (create, start, progress, complete, fail) through intent-named helpers instead of calling task-registry directly. A companion task-executor-policy module extracts the policy predicates and message-formatting functions that were inlined in task-registry.ts, cleanly separating concerns without introducing circular dependencies (the policy module only imports from task-registry.types.ts).

Key points:

• Behavioral equivalence for all registry interactions is preserved. The isTerminalTaskStatus / shouldAutoDeliverTaskStateChange / shouldAutoDeliverTaskTerminalUpdate rewrites are logically identical to their inlined predecessors.
• failTaskRunByRunId intentionally omits terminalOutcome, enforcing the domain constraint that a "blocked" outcome is only meaningful for succeeded tasks.
• The shouldSuppressDuplicateTerminalDelivery extraction correctly moves the pickPreferredRunIdTask lookup to the call site in task-registry.ts, keeping the policy function pure and testable.
• New test files cover both the executor flow (queued→running→succeeded and running→failed) and the policy logic (formatting, delivery predicates, suppression logic).
• markTaskRunLostById and cancelDetachedTaskRunById are added as forward-looking executor exports but are not yet wired to production callers — minor surface area addition consistent with the refactor scope.

Confidence Score: 5/5

Safe to merge — clean refactor with verified behavioral equivalence, no circular dependencies, and comprehensive new test coverage.

All findings are P2 or lower. The logic refactoring is behaviorally equivalent, the intentional semantic constraints (dropping terminalOutcome from the failure path) are clearly designed, and the new executor/policy split is well-structured. No runtime regressions identified.

No files require special attention.

_{Reviews (1): Last reviewed commit: "Merge branch 'main' into pr3/acp-executo..." | Re-trigger Greptile}