feat: Google Chat bridge with YOLO mode, text-based approvals, and Add-ons support

- Add normalizeEvent() to convert Workspace Add-ons event format to legacy ChatEvent
- Add wrapAddOnsResponse() for Add-ons response wrapping
- Mount chat bridge routes BEFORE A2A SDK catch-all handler
- Replace card button approvals with text-based approve/reject/always allow
- Add /reset, /yolo, /safe slash commands for session control
- Add YOLO mode tool approval dedup (filter auto-approved surfaces)
- Add extractCommandSummary() for concise tool card display
- Delegate auth to Cloud Run IAM when K_SERVICE env var detected
- Add JWT debug logging for token claim inspection

packages/a2a-server/src/http/app.ts

@@ -203,6 +203,27 @@ export async function createApp() {
       requestStorage.run({ req }, next);
     });
 
+    // Mount Google Chat bridge routes BEFORE A2A SDK routes.
+    // The A2A SDK's setupRoutes registers a catch-all jsonRpcHandler middleware
+    // at baseUrl="" that intercepts ALL POST requests and returns 400 for
+    // non-JSON-RPC payloads. Chat bridge must be registered first.
+    const chatBridgeUrl =
+      process.env['CHAT_BRIDGE_A2A_URL'] || process.env['CODER_AGENT_PORT']
+        ? `http://localhost:${process.env['CODER_AGENT_PORT'] || '8080'}`
+        : undefined;
+    if (chatBridgeUrl) {
+      expressApp.use(express.json());
+      const chatRoutes = createChatBridgeRoutes({
+        a2aServerUrl: chatBridgeUrl,
+        projectNumber: process.env['CHAT_PROJECT_NUMBER'],
+        debug: process.env['CHAT_BRIDGE_DEBUG'] === 'true',
+      });
+      expressApp.use(chatRoutes);
+      logger.info(
+        `[CoreAgent] Google Chat bridge enabled at /chat/webhook (A2A: ${chatBridgeUrl})`,
+      );
+    }
+
     const appBuilder = new A2AExpressApp(requestHandler);
     expressApp = appBuilder.setupRoutes(expressApp, '');
     expressApp.use(express.json());
@@ -306,23 +327,6 @@ export async function createApp() {
       }
     });
 
-    // Mount Google Chat bridge routes if configured
-    const chatBridgeUrl =
-      process.env['CHAT_BRIDGE_A2A_URL'] || process.env['CODER_AGENT_PORT']
-        ? `http://localhost:${process.env['CODER_AGENT_PORT'] || '8080'}`
-        : undefined;
-    if (chatBridgeUrl) {
-      const chatRoutes = createChatBridgeRoutes({
-        a2aServerUrl: chatBridgeUrl,
-        projectNumber: process.env['CHAT_PROJECT_NUMBER'],
-        debug: process.env['CHAT_BRIDGE_DEBUG'] === 'true',
-      });
-      expressApp.use(chatRoutes);
-      logger.info(
-        `[CoreAgent] Google Chat bridge enabled at /chat/webhook (A2A: ${chatBridgeUrl})`,
-      );
-    }
-
     expressApp.get('/tasks/:taskId/metadata', async (req, res) => {
       const taskId = req.params.taskId;
       let wrapper = agentExecutor.getTask(taskId);