M9: MCP Hub locale/correlation propagation, real Hub health check, fix stale test image

Fixed two concrete gaps in the MCP knowledge-search endpoint: no locale field
existed at all (now nl-BE/en-GB/fr-BE, wired to the knowledge provider's
existing language param), and the correlation ID was always freshly minted,
ignoring any inbound X-Correlation-Id header. Added a shared dependency and
applied it to all four MCP endpoints so Fleet Ops's own audit log preserves
the Hub's real correlation ID end to end.

MCP_HUB_BASE_URL/MCP_PROVIDER_ID were declared in .env.example but never read
anywhere. Since the Hub's own registration is catalog-driven (it never needs
Fleet Ops to push a registration call), wired mcp_hub_base_url for a real Hub
reachability health check instead of an unneeded self-registration call.

Renamed Fleet Ops's own internal audit tool labels mobilityops_* -> fleet_ops_*
(mirrored in contracts/mcp-tools.json with mobilityops_* kept as deprecated
aliases); documented that the live Hub connector's own dotted tool namespace
is a separate, Hub-owned naming layer, deliberately not touched.

Automation page's MCP card now shows real evidence (last tool/client/count/
timestamp, honest no-evidence state) instead of just the registration flag.

Also fixed a real methodology gap found mid-session: compose.yaml's api
service has no bind mount, so `docker compose run --rm api` silently tests a
stale image until rebuilt. Re-ran every local gate after rebuilding; fixed one
genuinely stale test assertion and two lint line-length errors surfaced by
that rebuild. 176 tests passing, ruff clean, mypy clean (50 files).

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

backend/app/services/integration_status.py

@@ -2,6 +2,7 @@ from __future__ import annotations
 
 from typing import Literal
 
+import httpx
 from sqlalchemy import func, select
 from sqlalchemy.orm import Session
 
@@ -153,6 +154,8 @@ def derive_mcp_hub_status(db: Session) -> McpHubIntegrationStatus:
     else:
         state = "no_evidence"
 
+    hub_reachable = _check_hub_reachable()
+
     return McpHubIntegrationStatus(
         registration_enabled=settings.mcp_hub_registration_enabled,
         state=state,
@@ -160,4 +163,18 @@ def derive_mcp_hub_status(db: Session) -> McpHubIntegrationStatus:
         last_tool=last_tool,
         last_client=last_client,
         last_called_at=last_called_at,
+        hub_reachable=hub_reachable,
     )
+
+
+def _check_hub_reachable() -> bool | None:
+    """Real Hub-side health signal (MCP Hub's own registration is catalog-driven on
+    its side, so this is the only thing Fleet Ops itself can honestly check).
+    `None` means not configured / not checked, never a guess."""
+    if not settings.mcp_hub_base_url:
+        return None
+    try:
+        response = httpx.get(f"{settings.mcp_hub_base_url.rstrip('/')}/health", timeout=1.5)
+        return response.status_code == 200
+    except httpx.HTTPError:
+        return False