auth: token contract v1 (aud windy_git, both issuers); CI for eternitas

- hub_jwt: aud list is ["windy_git"] (contract v1 array). Dropped
  "windy-git": that is Gitea's OIDC client_id, so a forge id_token would
  have passed the aud check. `type: human` is now REQUIRED (id_tokens have
  none), which makes accepting the discovery-URL issuer safe.
- runner job ceiling 30m -> 90m: eternitas's serial pytest is ~50 min and
  would have been killed mid-suite.
- eternitas (private) added to the GitHub status bridge.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

api/tests/test_invariants.py

@@ -314,7 +314,7 @@ def test_g36_unverified_human_jwt_is_refused_in_production():
     from api.app.config import Settings
 
     assert Settings().require_verified_jwt is True
-    assert Settings().hub_issuers == ["windy-identity"]
+    assert "windy-git" not in Settings().hub_audiences  # Gitea's client_id: id_token confusion
 
 
 def test_no_auth_bypass_env_var_anywhere():