fix(ui): UI/UX pass — connectivity probe, mobile overflow, real metrics, deep links (#85)

Found during a browser-driven audit of the whole app:

- connectivity banner showed permanently: pingServer() resolved
  undefined, which React Query treats as an error; returns boolean now
- Vite dev proxy now forwards /health so the probe actually measures
  the backend, and the API target is env-overridable (VITE_API_PROXY)
- auth-session removed from the persisted query cache — stale sessions
  no longer rehydrate into a false signed-in flash
- workspace Observability tab no longer shows fabricated random metrics
  ("87K Active User", fake performance/speed-test cards); the dashboard
  now aggregates real per-service metrics (CPU, memory, network, instances)
- service detail tabs write ?section= so tab state is shareable/deep-linked
- Security page auto-selects the first project instead of rendering blank
- People page user-creation form no longer overflows its card
  (minmax(0,1fr) grid tracks; same fix on env-var rows)
- page padding is responsive (px-4 sm:px-8) so mobile keeps content width;
  Projects header wraps instead of clipping the "+ new project" button
- template deploy modal shows a loading state while the session resolves
  instead of flashing the sign-in prompt
- audit log table strips the CIDR suffix from displayed IPs
- docs list excerpts no longer repeat the document title
- activity filter placeholder "Search search…" → "Search events…"
- workspace view tabs get more room: ⌘K button now waits for lg:

Generated with [Devin](https://devin.ai)

Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>

app/frontend/vite.config.ts

@@ -59,8 +59,12 @@ export default defineConfig({
     },
     proxy: {
       // Same-origin API path for dev - matches the nginx proxy in the shipped image
+      '/health': {
+        target: process.env.VITE_API_PROXY ?? 'http://localhost:8082',
+        changeOrigin: true,
+      },
       '/api': {
-        target: 'http://localhost:8082',
+        target: process.env.VITE_API_PROXY ?? 'http://localhost:8082',
         changeOrigin: true,
         ws: true,
       },