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.

tests/unit/domain-services.test.ts

@@ -24,7 +24,7 @@ describe("domain services", () => {
     const connection = createConnection();
 
     const rows = connection.db.prepare("select version from schema_migrations order by version asc").all() as Array<{ version: number }>;
-    expect(rows.map((row) => row.version)).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53]);
+    expect(rows.map((row) => row.version)).toEqual([1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 43, 44, 45, 46, 47, 48, 49, 50, 51, 52, 53, 54]);
     connection.close();
   });