fix: address PR #587 REQUEST_CHANGES for MCP namespace health (#543)

- Distinguish client_namespace vs offline_spawn probe sources; only IDE
  client probes prove namespace health and feed mutation gates.
- Record assessments in session; gate gitea_submit_pr_review and
  gitea_merge_pr when client-namespace health is unhealthy/non-proven.
- Mark test_mcp_conn.py offline-only; align recovery docs to client
  reconnect (no PID-kill/config-touch as canonical recovery).
- Rebase onto current master so #590 ledger isolation keeps
  TestMergePR.test_unknown_profile_blocks green.

gitea_mcp_server.py

@@ -2825,6 +2825,35 @@ _TERMINAL_REVIEW_ACTIONS = frozenset({"approve", "request_changes"})
 # remote + profile identity with TTL.
 _REVIEW_DECISION_LOCK: dict | None = None
 
+# Session-scoped live MCP namespace health assessments (#543).
+# Keyed by namespace name. Only client_namespace entries authorize mutations.
+_LIVE_NAMESPACE_HEALTH: dict[str, dict] = {}
+
+
+def _record_live_namespace_health(assessment: dict | None) -> None:
+    """Store a namespace health assessment for mutation gates."""
+    if not isinstance(assessment, dict):
+        return
+    ns = str(assessment.get("namespace") or "").strip()
+    if not ns:
+        return
+    _LIVE_NAMESPACE_HEALTH[ns] = {
+        "namespace": ns,
+        "healthy": bool(assessment.get("healthy")),
+        "ide_namespace_proven": bool(assessment.get("ide_namespace_proven")),
+        "probe_source": assessment.get("probe_source"),
+        "blocks_merge_workflow": bool(assessment.get("blocks_merge_workflow")),
+        "error_type": assessment.get("error_type"),
+        "required_tool": assessment.get("required_tool"),
+    }
+
+
+def _live_namespace_health_gate(task: str) -> list[str]:
+    """Fail closed on recorded broken/non-client IDE namespace health (#543)."""
+    return mcp_namespace_health.mutation_gate_from_session(
+        task, _LIVE_NAMESPACE_HEALTH
+    )
+
 
 def _decision_lock_binding(lock: dict | None = None) -> dict:
     """Resolve key fields for durable decision-lock storage."""
@@ -3515,6 +3544,11 @@ def _evaluate_pr_review_submission(
         reasons.extend(workflow_blockers)
         reasons.extend(review_workflow_load.recovery_handoff_without_replay())
         return result
+    if live:
+        ns_gate = _live_namespace_health_gate("review_pr")
+        if ns_gate:
+            reasons.extend(ns_gate)
+            return result
 
     if action not in _REVIEW_ACTIONS:
         reasons.append(
@@ -4616,6 +4650,12 @@ def gitea_merge_pr(
         reasons.extend(review_workflow_load.recovery_handoff_without_replay())
         return result
 
+    # Gate 0b — recorded live MCP namespace health must not be broken (#543).
+    ns_gate = _live_namespace_health_gate("merge_pr")
+    if ns_gate:
+        reasons.extend(ns_gate)
+        return result
+
     # Gate 1 — valid merge method (no API call on a bad method).
     if do not in _MERGE_METHODS:
         reasons.append(
@@ -9203,16 +9243,22 @@ def gitea_assess_mcp_namespace_health(
     config_path: str | None = None,
     profile: str | None = None,
     configured: bool = True,
+    probe_source: str | None = None,
 ) -> dict:
-    """Read-only: classify live MCP namespace health for required Gitea tools.
+    """Classify MCP namespace health for required Gitea tools (#543).
 
     Static FastMCP registration is not enough to prove a namespace works: IDE
     clients can keep a registered tool list while live calls fail with
-    ``client is closing: EOF``. This diagnostic accepts static registration
-    evidence plus live invocation evidence and returns fail-closed guidance for
-    reviewer/merger workflows.
+    ``client is closing: EOF``. Pass live IDE invocation evidence with
+    ``probe_source='client_namespace'``. Offline subprocess probes
+    (``test_mcp_conn.py``) must use ``probe_source='offline_spawn'`` and never
+    count as IDE proof.
+
+    Assessments are recorded in the session so live
+    ``gitea_submit_pr_review`` / ``gitea_merge_pr`` can fail closed when a
+    client-namespace probe reported unhealthy.
     """
-    return mcp_namespace_health.classify_namespace_probe(
+    result = mcp_namespace_health.classify_namespace_probe(
         namespace,
         required_tool=required_tool,
         registered_tools=registered_tools,
@@ -9221,7 +9267,10 @@ def gitea_assess_mcp_namespace_health(
         config_path=config_path,
         profile=profile,
         configured=configured,
+        probe_source=probe_source,
     )
+    _record_live_namespace_health(result)
+    return result
 
 
 @mcp.tool()