feat(channels): add group chat support for Telegram

- Add GroupGate class for group access control with three policies:
  disabled (default), allowlist, and open
- Implement mention gating: bot only responds when @mentioned or replied to
  in groups (configurable per-group)
- Extend Envelope type with isGroup, isMentioned, isReplyToBot fields
- Update TelegramAdapter to detect group context and mentions
- Add comprehensive documentation for group chat setup and troubleshooting

This enables using Qwen Code bots in Telegram groups with fine-grained
access control and mention-based activation to prevent noise.

Co-authored-by: Qwen-Coder <qwen-coder@alibabacloud.com>

packages/channels/base/src/AcpBridge.ts

@@ -61,13 +61,13 @@ export class AcpBridge extends EventEmitter {
     this.child.stderr?.on('data', (data: Buffer) => {
       const msg = data.toString().trim();
       if (msg) {
-        console.error('[AcpBridge]', msg);
+        process.stderr.write(`[AcpBridge] ${msg}\n`);
       }
     });
 
     this.child.on('exit', (code, signal) => {
-      console.error(
-        `[AcpBridge] Process exited (code=${code}, signal=${signal})`,
+      process.stderr.write(
+        `[AcpBridge] Process exited (code=${code}, signal=${signal})\n`,
       );
       this.connection = null;
       this.child = null;
@@ -197,6 +197,9 @@ export class AcpBridge extends EventEmitter {
         }
         break;
       }
+      default:
+        // Ignore other session update types
+        break;
     }
 
     this.emit('sessionUpdate', params);