78e7a4fefb
Harden the claim warning into a block: task_update action=claim on a task with unmet blockers is now rejected (no mutation) with the blocker list, instead of claiming-with-a-warning. Escapable with force=true, which claims anyway and keeps the "claimed despite unmet blockers" warning for the audit trail. Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>