Chat-wake tasks live and die with their reply run

Of the 202 tasks stranded in the backlog on July 9, 200 were "Reply to ..."
wake vehicles: every agent @mention creates a task plus a queued run, the
reply goes out, and nothing ever closed the task — a task with a completed
run is never enqueued again, so each one became a permanent zombie row. On
top of that, every message in an active thread minted a fresh wake even when
the target already had one queued, multiplying runs that would each read the
same conversation.

The lifecycle contract, made explicit:
- The reply run IS the wake task's deliverable. Completing a chat_mention
  run now closes its task (backlog/in_progress -> done, via the audited
  status path). Tasks an agent moved to review are left alone.
- One pending wake per (agent, thread): wakeFromMention returns the queued
  run instead of minting a duplicate — that run reads the thread's newest
  messages when it executes anyway.
- Migration 054 heals existing rows: wake tasks whose runs are all spent
  close as done; in-flight wakes keep working. This also stops Fix 1's
  retry-budget healing from resurrecting 31 stale replies on next launch.

The chat-governance loop test now completes each pending wake run between
posts, matching how the exchange actually interleaves in production.

src/main/database/schema.ts

@@ -52,6 +52,7 @@ import { financeSalesDepartmentsSchema } from "./migrations/050-finance-sales-de
 import { purgeRuntimeSnapshotBloatSchema } from "./migrations/051-purge-runtime-snapshot-bloat";
 import { avatarImagesSchema } from "./migrations/052-avatar-images";
 import { autonomousPauseSchema } from "./migrations/053-autonomous-pause";
+import { closeStaleWakeTasksSchema } from "./migrations/054-close-stale-wake-tasks";
 
 interface Migration {
   version: number;
@@ -113,6 +114,7 @@ const MIGRATIONS: Migration[] = [
   { version: 51, name: "purge_runtime_snapshot_bloat", sql: purgeRuntimeSnapshotBloatSchema },
   { version: 52, name: "avatar_images", sql: avatarImagesSchema },
   { version: 53, name: "autonomous_pause", sql: autonomousPauseSchema },
+  { version: 54, name: "close_stale_wake_tasks", sql: closeStaleWakeTasksSchema },
 ];
 
 const SCHEMA_VERSION = MIGRATIONS[MIGRATIONS.length - 1].version;