refactor(startup): simplify stack to Tauri-managed OpenFang + optional ChromeDriver

- Remove OpenFang CLI dependency from startup scripts
- OpenFang now bundled with Tauri and managed via gateway_start/gateway_status commands
- Add bootstrap screen in App.tsx to auto-start local gateway before UI loads
- Update Makefile: replace start-no-gateway with start-desktop-only
- Fix gateway config endpoints: use /api/config instead of /api/config/quick
- Add Playwright dependencies for future E2E testing

desktop/vite.config.ts

@@ -29,7 +29,8 @@ export default defineConfig(async () => ({
       ignored: ["**/src-tauri/**"],
     },
     proxy: {
-      // Proxy /api requests to OpenFang (port 50051) or OpenClaw (port 18789)
+      // Proxy /api requests to OpenFang Kernel (port 50051)
+      // OpenFang is managed by Tauri app - started via gateway_start command
       '/api': {
         target: 'http://127.0.0.1:50051',
         changeOrigin: true,