fix: derive demo-manifest MCP Hub status from real tool-call evidence

The demo manifest still reported the MCP Hub integration as operational purely
because MCP_HUB_REGISTRATION_ENABLED was set, while the integration status page
had already moved to evidence-based status in Batch 4. Registration is
catalog-driven on the Hub's side, so the flag alone proves nothing; reuse
derive_mcp_hub_status() so "operational" requires real recorded mcp_tool_request
calls.

No change to the MCP integration contract: the four read-only routes, service
token and client id handling, inbound X-Correlation-Id preservation, the locale
field on search-knowledge and the provider/correlation_id response fields were
verified as already correct at deployed revision 727c19a and left untouched.

backend/app/services/demo_manifest.py

@@ -11,7 +11,7 @@ from app.models.booking import Booking
 from app.models.data_quality import DataQualityIssue
 from app.models.outbox import OutboxEvent
 from app.schemas import DemoIntegrationSummaryOut, DemoManifestOut, DemoScenarioOut
-from app.services.integration_status import derive_n8n_status
+from app.services.integration_status import derive_mcp_hub_status, derive_n8n_status
 from app.services.knowledge import get_knowledge_provider
 
 settings = get_settings()
@@ -124,6 +124,7 @@ def _scenarios(db: Session) -> list[DemoScenarioOut]:
 def _integrations(db: Session) -> list[DemoIntegrationSummaryOut]:
     n8n = derive_n8n_status(db)
     knowledge_health = get_knowledge_provider().health()
+    mcp_hub = derive_mcp_hub_status(db)
 
     return [
         DemoIntegrationSummaryOut(
@@ -147,11 +148,13 @@ def _integrations(db: Session) -> list[DemoIntegrationSummaryOut]:
         ),
         DemoIntegrationSummaryOut(
             key="mcp_hub",
-            status_code="operational" if settings.mcp_hub_registration_enabled else "notConnected",
+            # `MCP_HUB_REGISTRATION_ENABLED` on its own proves nothing: registration is
+            # catalog-driven on the Hub's side, so the flag only says Fleet Ops expects
+            # to be called. Only real recorded `mcp_tool_request` calls make this
+            # "operational" -- same evidence rule the integration status page uses.
+            status_code="operational" if mcp_hub.state == "operational" else "notConnected",
             detail_code=(
-                "mcpDetailEnabled"
-                if settings.mcp_hub_registration_enabled
-                else "mcpDetailNotConnected"
+                "mcpDetailEnabled" if mcp_hub.state == "operational" else "mcpDetailNotConnected"
             ),
             detail_params={},
         ),