feat: add a runtime diagnostics page

Adds GET /api/clouds/:cloud/diagnostics and a Diagnostics page in the
General nav. The report combines, in one call:

- runtime reachability, latency, version and edition from /_floci/health
- every service the runtime emulates, with the console pages backed by it
- per-console-service probes (the existing status check)
- EC2 instance containers from /_floci/diagnose
- console uptime, sign-in mode and active session count

Each source is optional, so a down runtime still yields a partial report.

packages/frontend/src/api/queries/cloudQueries.ts

@@ -1,5 +1,6 @@
 import {useQuery} from '@tanstack/react-query'
 import {
+    getCloudDiagnostics,
     getCloudResource,
     getCloudServiceStatus,
     getCloudStatus,
@@ -20,6 +21,7 @@ export const cloudQueryKeys = {
     clouds: ['clouds'] as const,
     services: (cloud: CloudProvider) => ['cloud-services', cloud] as const,
     status: (cloud: CloudProvider) => ['cloud-status', cloud] as const,
+    diagnostics: (cloud: CloudProvider) => ['cloud-diagnostics', cloud] as const,
     serviceStatus: (cloud: CloudProvider, service: CloudServiceType) =>
         ['cloud-service-status', cloud, service] as const,
     resources: (cloud: CloudProvider, service: CloudServiceType) =>
@@ -53,6 +55,15 @@ export function useCloudStatusQuery(cloud: CloudProvider, options: {refetchInter
     })
 }
 
+/** Full runtime report; polled slowly because it probes every console service. */
+export function useCloudDiagnosticsQuery(cloud: CloudProvider) {
+    return useQuery({
+        queryKey: cloudQueryKeys.diagnostics(cloud),
+        queryFn: ({signal}) => getCloudDiagnostics(cloud, signal),
+        refetchInterval: 30_000,
+    })
+}
+
 /** Health of the single service being viewed, rather than of the whole cloud. */
 export function useCloudServiceStatusQuery(
     cloud: CloudProvider,