feat(web-server): add proxy configuration API routes

- GET /api/proxy returns current proxy config

- PUT /api/proxy updates proxy settings in config.yaml

- POST /api/proxy/test tests remote connection

- register routes in web server index

src/web-server/index.ts

@@ -51,6 +51,10 @@ export async function startServer(options: ServerOptions): Promise<ServerInstanc
   const { usageRoutes } = await import('./usage-routes');
   app.use('/api/usage', usageRoutes);
 
+  // Proxy settings routes (Phase 5)
+  const proxyRoutes = (await import('./routes/proxy-routes')).default;
+  app.use('/api/proxy', proxyRoutes);
+
   // Dev mode: use Vite middleware for HMR
   if (options.dev) {
     const { createServer: createViteServer } = await import('vite');

src/web-server/routes/proxy-routes.ts

@@ -0,0 +1,93 @@
+/**
+ * Proxy Routes - API endpoints for proxy configuration
+ *
+ * Provides REST endpoints for managing CLIProxyAPI connection settings:
+ * - GET /api/proxy - Get proxy configuration
+ * - PUT /api/proxy - Update proxy configuration
+ * - POST /api/proxy/test - Test remote connection
+ */
+
+import { Router, Request, Response } from 'express';
+import { loadOrCreateUnifiedConfig, saveUnifiedConfig } from '../../config/unified-config-loader';
+import { testConnection } from '../../cliproxy/remote-proxy-client';
+import { DEFAULT_PROXY_CONFIG, ProxyConfig } from '../../config/unified-config-types';
+
+const router = Router();
+
+/**
+ * GET /api/proxy - Get proxy configuration
+ */
+router.get('/', async (_req: Request, res: Response) => {
+  try {
+    const config = await loadOrCreateUnifiedConfig();
+    res.json(config.proxy || DEFAULT_PROXY_CONFIG);
+  } catch (error) {
+    console.error('[proxy-routes] Failed to load proxy config:', error);
+    res.status(500).json({ error: 'Failed to load proxy config' });
+  }
+});
+
+/**
+ * PUT /api/proxy - Update proxy configuration
+ */
+router.put('/', async (req: Request, res: Response) => {
+  try {
+    const config = await loadOrCreateUnifiedConfig();
+    const updates = req.body as Partial<ProxyConfig>;
+
+    // Deep merge with defaults and current config
+    config.proxy = {
+      remote: {
+        ...DEFAULT_PROXY_CONFIG.remote,
+        ...config.proxy?.remote,
+        ...updates.remote,
+      },
+      fallback: {
+        ...DEFAULT_PROXY_CONFIG.fallback,
+        ...config.proxy?.fallback,
+        ...updates.fallback,
+      },
+      local: {
+        ...DEFAULT_PROXY_CONFIG.local,
+        ...config.proxy?.local,
+        ...updates.local,
+      },
+    };
+
+    await saveUnifiedConfig(config);
+    res.json(config.proxy);
+  } catch (error) {
+    console.error('[proxy-routes] Failed to save proxy config:', error);
+    res.status(500).json({ error: 'Failed to save proxy config' });
+  }
+});
+
+/**
+ * POST /api/proxy/test - Test remote proxy connection
+ */
+router.post('/test', async (req: Request, res: Response) => {
+  try {
+    const { host, port, protocol, authToken, allowSelfSigned } = req.body;
+
+    if (!host || !port) {
+      res.status(400).json({ error: 'Host and port are required' });
+      return;
+    }
+
+    const status = await testConnection({
+      host,
+      port: typeof port === 'number' ? port : parseInt(port, 10),
+      protocol: protocol || 'http',
+      authToken,
+      allowSelfSigned: allowSelfSigned || false,
+      timeout: 5000,
+    });
+
+    res.json(status);
+  } catch (error) {
+    console.error('[proxy-routes] Failed to test connection:', error);
+    res.status(500).json({ error: 'Failed to test connection' });
+  }
+});
+
+export default router;