fix: wire audit loop into worker completion path (pushback delivery, escalate, packet preamble)

Audit-loop wiring, worker completion path only: after the final
write-back (and only when the final is completed/failed, not quota,
not cancelled, not goal-converted, and the task carries audit_loop),
collect this attempt's deterministic gate results (execution,
goal_verify only when host reported goal_met, capability /
required_tools / gateway as passed-or-inapplicable markers, since a
pre-dispatch gate rejection early-returns before any runner round
and requeueing it would deterministically re-fail the same gate)
and call audit_loop_evaluate. Pushback stores the packet JSON in
tasks.audit_loop_packet and CAS-requeues the task; the next claim
prepends the packet preamble to prompt (and goal) with a data-only
separator, DB prompt untouched. Pass clears the packet. Escalate
sets failed (VALID_STATUSES has no needs_review, never invented)
with an escalation error and clears the packet; subjective
needs_review leaves the outcome untouched and only audits.
New tasks.audit_loop / audit_loop_packet columns follow the
attempts DDL pattern in worker ensure, server migrate, PG schema,
PG backfill, migrations backfill, and POST /tasks accepts
audit_loop (True/1 only, coordinator tasks rejected like v9).
Coordinator parent tasks return via _run_coordinator before the
attempt loop and coordinator children never inherit audit_loop,
so coordinator wiring is left as legacy, unchanged.

cloud/migrations.py

@@ -223,7 +223,8 @@ def migrate_sqlite_to_postgres(sqlite_path, pg_conn=None, tables=None):
                     _existing = set()
                 for _col in ("agent_name", "agent_version",
                              "agent_instructions", "agent_tools",
-                             "agent_tool_approvals"):
+                             "agent_tool_approvals", "audit_loop",
+                             "audit_loop_packet"):
                     if _col not in _existing:
                         try:
                             pg_conn.execute(