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.

decnet/ttp/impl/_state.py

@@ -40,7 +40,7 @@ def apply_ceiling(base: float, state: "RuleState") -> float:
     """Apply the operator's confidence ceiling, downward only.
 
     A ``clipped`` state with ``confidence_max < 1.0`` clamps the emitted
-    confidence to ``min(base, base * ceiling)``. Any other state is a
+    confidence to ``min(base, ceiling)``. Any other state is a
     no-op. The clamp is downward by construction — operator clips can
     never raise a rule's confidence above its YAML-declared base, per
     TTP_TAGGING.md §"Confidence model".
@@ -50,7 +50,7 @@ def apply_ceiling(base: float, state: "RuleState") -> float:
     ceiling = state.confidence_max
     if ceiling is None or ceiling >= 1.0:
         return base
-    return min(base, base * ceiling)
+    return min(base, ceiling)
 
 
 __all__ = ["is_active", "apply_ceiling"]