Merge master into fix/issue-714-session-context-immutability

Resolve gitea_mcp_server.py conflicts after master advanced with #724
(side-effect-free resolver), #725 (merger lease), #728 (PR-sync), and
#702 stale-binding recovery:

- Keep #714 fail-closed session immutability: no auto profile switch
  (_ensure_matching_profile / _try_auto_switch_for_operation).
- Retain master #709 _authenticated_actor identity helper.
- Preserve resolve-path auto_recover=False (#685) and report-only
  stale_binding_recovery coexistence with runtime_reconnect_required.
- Cross-host / cross-repository substitution still fails closed without
  mutating the pinned session context.
- Regression coverage for merge coexistence, dual-module identity-cache
  isolation in conftest, and structured unknown_task fail-closed.

Closes #714 conflict remediation path for PR #715.

tests/conftest.py

@@ -99,6 +99,20 @@ def _reset_mutation_authority(monkeypatch):
     monkeypatch.setattr(gitea_config, "_active_profile_override", None)
     monkeypatch.setattr(mcp_server, "_MUTATION_AUTHORITY", None)
     monkeypatch.setattr(mcp_server, "_IDENTITY_CACHE", {})
+    # #714: clear both module namespaces. mcp_server.py execs gitea_mcp_server.py
+    # into its own globals, so `import gitea_mcp_server` is a separate module
+    # object with its own identity caches; leaving it dirty leaks login across
+    # tests that import the implementation module directly.
+    try:
+        import gitea_mcp_server as _gitea_impl
+
+        monkeypatch.setattr(_gitea_impl, "_IDENTITY_CACHE", {})
+        if hasattr(_gitea_impl, "_ACTOR_IDENTITY_CACHE"):
+            monkeypatch.setattr(_gitea_impl, "_ACTOR_IDENTITY_CACHE", {})
+    except Exception:
+        pass
+    if hasattr(mcp_server, "_ACTOR_IDENTITY_CACHE"):
+        monkeypatch.setattr(mcp_server, "_ACTOR_IDENTITY_CACHE", {})
     monkeypatch.setattr(mcp_server, "_REVIEW_DECISION_LOCK", None)
     monkeypatch.setattr(mcp_server, "_LIVE_NAMESPACE_HEALTH", {})
     monkeypatch.setattr(mcp_server, "_preflight_whoami_called", False)