feat: enforce live-namespace block in review/merge state machine (#543 AC5)

The namespace health check (05fdcee) classified a false-ready namespace but
only returned an advisory blocks_merge_workflow flag; nothing in the merge
gate consumed it. Wire it in so a broken live namespace hard-blocks merge.

- review_merge_state_machine.assess_workflow_blockers: add live_namespace_broken
  blocker (registered-in-FastMCP but not callable-through-namespace).
- assess_state_advancement: forward **blocker_kwargs so can_approve/can_merge/
  workflow_status honor the full blocker set (also fixes latent drop of
  mcp_reconnect_failed/stale_capability_state through those paths).
- gitea_assess_review_merge_state_machine tool: accept live_namespace_broken and
  thread it through all state-machine calls.
- Tests: prove can_merge/workflow_status/tool block on live_namespace_broken even
  with every review state + pre-merge gate satisfied; bridge classify verdict.
- Docs: enforcement section wiring blocks_merge_workflow -> live_namespace_broken.

Co-Authored-By: Claude Opus 4.8 (1M context) <[email protected]>

gitea_mcp_server.py

@@ -7792,40 +7792,45 @@ def gitea_assess_review_merge_state_machine(
     pre_merge_gates: dict[str, bool] | None = None,
     infra_stop: bool = False,
     capability_blocked: bool = False,
+    live_namespace_broken: bool = False,
     recovery_handoff_text: str | None = None,
     final_report_text: str | None = None,
 ) -> dict:
-    """Read-only: assess enforced PR review/merge workflow state (#290)."""
+    """Read-only: assess enforced PR review/merge workflow state (#290).
+
+    ``live_namespace_broken`` fails review/merge closed when the live MCP
+    namespace call path is unusable even though the tool is registered in
+    FastMCP (#543 AC5). Supply the ``blocks_merge_workflow`` verdict from
+    ``gitea_assess_mcp_namespace_health``.
+    """
     completion = state_completion or {}
-    blockers = review_merge_state_machine.assess_workflow_blockers(
-        infra_stop=infra_stop,
-        capability_blocked=capability_blocked,
-    )
+    blocker_kwargs = {
+        "infra_stop": infra_stop,
+        "capability_blocked": capability_blocked,
+        "live_namespace_broken": live_namespace_broken,
+    }
+    blockers = review_merge_state_machine.assess_workflow_blockers(**blocker_kwargs)
     result = {
         "workflow": review_merge_state_machine.workflow_status(
             completion,
-            infra_stop=infra_stop,
-            capability_blocked=capability_blocked,
+            **blocker_kwargs,
         ),
         "blockers": blockers,
         "approve": review_merge_state_machine.can_approve(
             completion,
-            infra_stop=infra_stop,
-            capability_blocked=capability_blocked,
+            **blocker_kwargs,
         ),
         "merge": review_merge_state_machine.can_merge(
             completion,
             pre_merge_gates=pre_merge_gates,
-            infra_stop=infra_stop,
-            capability_blocked=capability_blocked,
+            **blocker_kwargs,
         ),
     }
     if target_state:
         result["advancement"] = review_merge_state_machine.assess_state_advancement(
             completion,
             target_state=target_state,
-            infra_stop=infra_stop,
-            capability_blocked=capability_blocked,
+            **blocker_kwargs,
         )
     if recovery_handoff_text is not None:
         result["recovery_handoff"] = (