feat(copilot): add raw settings API and model mapping routes

- add GET/PUT /api/copilot/settings/raw for copilot.settings.json

- update PUT /api/copilot/config to handle model mapping fields

- sync model mappings between settings file and unified config

src/web-server/routes.ts

@@ -1675,6 +1675,13 @@ apiRoutes.put('/copilot/config', (req: Request, res: Response): void => {
         config.copilot?.wait_on_limit ??
         DEFAULT_COPILOT_CONFIG.wait_on_limit,
       model: updates.model ?? config.copilot?.model ?? DEFAULT_COPILOT_CONFIG.model,
+      // Model mapping for opus/sonnet/haiku tiers
+      opus_model:
+        updates.opus_model !== undefined ? updates.opus_model : config.copilot?.opus_model,
+      sonnet_model:
+        updates.sonnet_model !== undefined ? updates.sonnet_model : config.copilot?.sonnet_model,
+      haiku_model:
+        updates.haiku_model !== undefined ? updates.haiku_model : config.copilot?.haiku_model,
     };
 
     saveUnifiedConfig(config);
@@ -1756,3 +1763,97 @@ apiRoutes.post('/copilot/daemon/stop', async (_req: Request, res: Response): Pro
     res.status(500).json({ error: (error as Error).message });
   }
 });
+
+/**
+ * GET /api/copilot/settings/raw - Get raw copilot.settings.json
+ * Returns the raw JSON content for editing in the code editor
+ */
+apiRoutes.get('/copilot/settings/raw', (_req: Request, res: Response): void => {
+  try {
+    const settingsPath = path.join(getCcsDir(), 'copilot.settings.json');
+    const config = loadOrCreateUnifiedConfig();
+    const copilotConfig = config.copilot ?? DEFAULT_COPILOT_CONFIG;
+
+    // Default model for all tiers
+    const defaultModel = copilotConfig.model;
+
+    // If file doesn't exist, return default structure with all model mappings
+    if (!fs.existsSync(settingsPath)) {
+      // Create settings structure matching CLIProxy pattern - always include all model mappings
+      const defaultSettings = {
+        env: {
+          ANTHROPIC_BASE_URL: `http://localhost:${copilotConfig.port}`,
+          ANTHROPIC_AUTH_TOKEN: 'copilot-managed',
+          ANTHROPIC_MODEL: defaultModel,
+          ANTHROPIC_DEFAULT_OPUS_MODEL: copilotConfig.opus_model || defaultModel,
+          ANTHROPIC_DEFAULT_SONNET_MODEL: copilotConfig.sonnet_model || defaultModel,
+          ANTHROPIC_DEFAULT_HAIKU_MODEL: copilotConfig.haiku_model || defaultModel,
+        },
+      };
+
+      res.json({
+        settings: defaultSettings,
+        mtime: Date.now(),
+        path: `~/.ccs/copilot.settings.json`,
+        exists: false,
+      });
+      return;
+    }
+
+    const content = fs.readFileSync(settingsPath, 'utf-8');
+    const settings = JSON.parse(content);
+    const stat = fs.statSync(settingsPath);
+
+    res.json({
+      settings,
+      mtime: stat.mtimeMs,
+      path: `~/.ccs/copilot.settings.json`,
+      exists: true,
+    });
+  } catch (error) {
+    res.status(500).json({ error: (error as Error).message });
+  }
+});
+
+/**
+ * PUT /api/copilot/settings/raw - Save raw copilot.settings.json
+ * Saves the raw JSON content from the code editor
+ */
+apiRoutes.put('/copilot/settings/raw', (req: Request, res: Response): void => {
+  try {
+    const { settings, expectedMtime } = req.body;
+    const settingsPath = path.join(getCcsDir(), 'copilot.settings.json');
+
+    // Check for conflict if file exists and expectedMtime provided
+    if (fs.existsSync(settingsPath) && expectedMtime) {
+      const stat = fs.statSync(settingsPath);
+      if (Math.abs(stat.mtimeMs - expectedMtime) > 1000) {
+        res.status(409).json({ error: 'File modified externally', mtime: stat.mtimeMs });
+        return;
+      }
+    }
+
+    // Write settings file atomically
+    const tempPath = settingsPath + '.tmp';
+    fs.writeFileSync(tempPath, JSON.stringify(settings, null, 2) + '\n');
+    fs.renameSync(tempPath, settingsPath);
+
+    // Also sync model mappings back to unified config
+    const config = loadOrCreateUnifiedConfig();
+    const env = settings.env || {};
+
+    config.copilot = {
+      ...(config.copilot ?? DEFAULT_COPILOT_CONFIG),
+      model: env.ANTHROPIC_MODEL || config.copilot?.model || DEFAULT_COPILOT_CONFIG.model,
+      opus_model: env.ANTHROPIC_DEFAULT_OPUS_MODEL || undefined,
+      sonnet_model: env.ANTHROPIC_DEFAULT_SONNET_MODEL || undefined,
+      haiku_model: env.ANTHROPIC_DEFAULT_HAIKU_MODEL || undefined,
+    };
+    saveUnifiedConfig(config);
+
+    const stat = fs.statSync(settingsPath);
+    res.json({ success: true, mtime: stat.mtimeMs });
+  } catch (error) {
+    res.status(500).json({ error: (error as Error).message });
+  }
+});