feat: Add Wild Central web app (Central-only UI)

Extract Central pages from the wild-cloud web app into a standalone
React app for Wild Central. Includes:

- Central overview, DNS, DHCP, Firewall, VPN, Ingress, CrowdSec pages
- Simplified sidebar with Central-only navigation
- Branding updated to "Wild Central"
- All Cloud-specific pages, components, hooks, and API services removed
- TypeScript type-check and production build pass

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

web/public/manifest.json

@@ -0,0 +1,15 @@
+{
+  "short_name": "Wild Cloud",
+  "name": "Wild Cloud Central",
+  "icons": [
+    {
+      "src": "favicon.svg",
+      "sizes": "any",
+      "type": "image/svg+xml"
+    }
+  ],
+  "start_url": ".",
+  "display": "standalone",
+  "theme_color": "#0ea5e9",
+  "background_color": "#ffffff"
+}