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/cloudProxyClient.ts

@@ -6,6 +6,7 @@ import type {
   CloudServiceStatus,
   CloudServiceType,
   CloudStatus,
+  RuntimeDiagnostics,
 } from "@/types/cloud";
 import type {
   AppConfigConfigurationProfile,
@@ -86,6 +87,18 @@ export async function getCloudStatus(
   return res.data;
 }
 
+export async function getCloudDiagnostics(
+  cloud: CloudProvider,
+  signal?: AbortSignal,
+): Promise<RuntimeDiagnostics> {
+  const res = await apiClient.call<RuntimeDiagnostics>(
+    apiEndpointKeys.clouds.diagnostics,
+    requestOptions(cloud, "cloud-proxy", { signal }),
+    { cloud },
+  );
+  return res.data;
+}
+
 export async function getCloudServiceStatus(
   cloud: CloudProvider,
   service: CloudServiceType,