fix(security): close MEDIUM ASVS findings — JWT pinning, SSE tickets, SSRF, mTLS pin, rate limits + correctness bugs

Auth (V2.1.1/V3.1.2, V2.1.3, V3.1.1):
- Pin JWT iss/aud/typ at mint and require+verify them at decode; revocation
  (jti denylist + tokens_valid_from) still enforced.
- Change-password now requires min_length=12.
- SSE auth moves off JWT-in-URL to a single-use 60s opaque ticket
  (POST /auth/sse-ticket); raw JWT in query no longer authenticates a stream.
  Removed dead fail-open get_stream_user helper.

Egress (V5.1.1, V9.1.1/V14.1.3):
- Webhook delivery + CRUD reject SSRF destinations (private/loopback/link-local/
  metadata, IPv4-mapped, multi-A-record) via resolved-IP validation, pin to the
  vetted IP, and never auto-follow redirects. Opt-out via DECNET_WEBHOOK_ALLOW_PRIVATE.
- UpdaterClient pins the worker leaf cert SHA-256 against the stored per-host
  fingerprint (fail closed on missing/mismatch); DECNET_VERIFY_HOSTNAME now
  defaults True.

Hardening (V13.1.3, V4.1.4, V13.1.2):
- Rate-limit change-password (5/min), enroll-bundle (10/min), webhook-create
  (20/min), host-delete (20/min) via the existing slowapi limiter.
- Correct false 'global auth middleware' comment; document enroll-bundle proxy
  trust.

Correctness (BUG-7..11):
- BUG-7 unbound bus in finally; BUG-8 apply_ceiling clamps to min(base,ceiling);
  BUG-9 commit before emit; BUG-10 multi-actor rearm for sub-threshold identities;
  BUG-11 normalize naive timestamps to UTC.

Already-closed (no change): V14.1.1, V2.1.2/V3.1.3, V5.1.2. Tests added for
every fix; unanimous adversarial review.

tests/orchestrator/test_worker_integration.py

@@ -276,6 +276,29 @@ async def test_one_tick_email_branch_records_orchestrator_email(
     assert ev.payload["mail_decky_uuid"] == mail_decky.uuid
 
 
+@pytest.mark.asyncio
+async def test_smtp_probe_listener_get_bus_raises_no_unbound_error(
+    repo, monkeypatch,
+) -> None:
+    """BUG-7 regression: if get_bus() raises, the finally block must not
+    produce an UnboundLocalError on ``bus``; the function must return
+    cleanly (RuntimeError is logged+swallowed by the outer except handler)."""
+    import asyncio
+    from decnet.orchestrator import worker as _w
+
+    def bad_get_bus(**_kw):
+        raise RuntimeError("bus factory unavailable")
+
+    monkeypatch.setattr(_w, "get_bus", bad_get_bus)
+
+    shutdown = asyncio.Event()
+    shutdown.set()
+
+    # Before fix: UnboundLocalError escaped from finally because ``bus``
+    # was never assigned.  After fix: completes without any exception.
+    await _w._run_smtp_probe_listener(repo, shutdown)
+
+
 @pytest.mark.asyncio
 async def test_tick_is_noop_when_no_running_deckies(repo, fake_bus, monkeypatch):
     called = False