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/api/auth/test_bulk_revocation.py

@@ -18,7 +18,14 @@ import pytest
 from sqlalchemy import select
 
 from decnet.env import DECNET_ADMIN_USER, DECNET_ADMIN_PASSWORD
-from decnet.web.auth import ALGORITHM, SECRET_KEY, get_password_hash
+from decnet.web.auth import (
+    ALGORITHM,
+    JWT_AUDIENCE,
+    JWT_ISSUER,
+    JWT_TYPE,
+    SECRET_KEY,
+    get_password_hash,
+)
 from decnet.web.db.models import User
 from decnet.web.dependencies import repo
 
@@ -54,7 +61,17 @@ def _aged_token(uuid: str, *, seconds_old: int = 30) -> str:
     change sets to 'now', so it is deterministically revoked once bumped."""
     now = int(time.time())
     return jwt.encode(
-        {"uuid": uuid, "jti": f"aged-{uuid}", "iat": now - seconds_old, "exp": now + 3600},
+        {
+            "uuid": uuid,
+            "jti": f"aged-{uuid}",
+            "iat": now - seconds_old,
+            "exp": now + 3600,
+            # The verifier now pins issuer/audience/type (V2.1.1 / V3.1.2); a
+            # manually-encoded token must carry them or decode rejects it.
+            "iss": JWT_ISSUER,
+            "aud": JWT_AUDIENCE,
+            "typ": JWT_TYPE,
+        },
         SECRET_KEY, algorithm=ALGORITHM,
     )