Send the portal the failure count its own tile shows

The portal card's "Failures 24h" had read 0 since failures_24h left
HealthSummary: that commit noted nothing read the field, which was true of this
repo and not of the portal in index/, where health is an opaque JSON blob with
no schema to catch the removal.

Restored on the connector rather than in /summary — no screen here reads it, and
it is folded from /observability/flows?hours=24, the same endpoint and window the
app's Home tile sums, so the two cannot drift apart again.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_016ZeGnqVsf5VHQqvz4HdUhN

backend/fluksio/cloud/connector.py

@@ -255,19 +255,32 @@ class CloudConnector:
         Fetched through the same in-process transport as everything else, with
         a short-lived local token: the observability API is authenticated, and
         this process is entitled to mint one for the enrolling user.
+
+        ``failures_24h`` is added here rather than by ``/summary``: it is the
+        portal's tile and nothing on this installation reads it, and summing
+        the same rollups over the same window the app's own Home tile sums
+        keeps the two from drifting apart the way they already did once.
         """
         from fluksio.core import security
 
         token = security.create_access_token(config.local_user_id, timedelta(minutes=5))
+        headers = {"Authorization": f"Bearer {token}"}
         try:
             async with self._client() as client:
                 response = await client.get(
-                    "/api/v1/observability/summary",
-                    headers={"Authorization": f"Bearer {token}"},
+                    "/api/v1/observability/summary", headers=headers
                 )
-            if response.status_code == 200:
+                if response.status_code != 200:
+                    return None
                 summary: dict[str, Any] = response.json()
-                return summary
+                rollups = await client.get(
+                    "/api/v1/observability/flows",
+                    params={"hours": 24},
+                    headers=headers,
+                )
+            if rollups.status_code == 200:
+                summary["failures_24h"] = sum(row["errors"] for row in rollups.json())
+            return summary
         except Exception:
             logger.debug("Could not collect a health summary for the portal")
         return None