fix: address review findings for grammY Telegram adapter

- Fix misleading 'unde***' log when ctx.from is undefined; use 'unknown'
  to match the Slack/Discord adapter pattern
- Log post-startup bot runtime errors before reject() (no-op after
  onStart fires but errors are now visible in logs)
- Add debug log when message is dropped due to no handler registered
- Add stop() unit test to guard against grammY API rename regressions

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

packages/adapters/src/chat/telegram/adapter.test.ts

@@ -234,6 +234,16 @@ describe('TelegramAdapter', () => {
     });
   });
 
+  describe('stop()', () => {
+    test('should call bot.stop()', () => {
+      const adapter = new TelegramAdapter('fake-token-for-testing');
+      const mockStop = mock(() => undefined);
+      (adapter.getBot() as unknown as { stop: typeof mockStop }).stop = mockStop;
+      adapter.stop();
+      expect(mockStop).toHaveBeenCalledTimes(1);
+    });
+  });
+
   describe('start()', () => {
     beforeEach(() => {
       mockLogger.warn.mockClear();

packages/adapters/src/chat/telegram/adapter.ts

@@ -176,7 +176,7 @@ export class TelegramAdapter implements IPlatformAdapter {
       const userId = ctx.from?.id;
       if (!isUserAuthorized(userId, this.allowedUserIds)) {
         // Log unauthorized attempt (mask user ID for privacy)
-        const maskedId = `${String(userId).slice(0, 4)}***`;
+        const maskedId = userId !== undefined ? `${String(userId).slice(0, 4)}***` : 'unknown';
         getLog().info({ maskedUserId: maskedId }, 'telegram.unauthorized_message');
         return; // Silent rejection
       }
@@ -185,6 +185,11 @@ export class TelegramAdapter implements IPlatformAdapter {
         const conversationId = this.getConversationId(ctx);
         // Fire-and-forget - errors handled by caller
         void this.messageHandler({ conversationId, message, userId });
+      } else {
+        // Intentional: message dropped silently if handler not registered yet.
+        // In production the server always calls onMessage() before start(); this
+        // path only surfaces during development or misconfiguration.
+        getLog().debug({ chatId: ctx.chat?.id }, 'telegram.message_dropped_no_handler');
       }
     });
 
@@ -208,7 +213,11 @@ export class TelegramAdapter implements IPlatformAdapter {
               },
             })
             .catch((err: unknown) => {
-              reject(err instanceof Error ? err : new Error(String(err)));
+              const error = err instanceof Error ? err : new Error(String(err));
+              // Log post-startup crashes — after onStart fires the reject() below is a no-op
+              // (Promise already settled), but the error should still be observable in logs.
+              getLog().error({ err: error }, 'telegram.bot_runtime_error');
+              reject(error);
             });
         });
         getLog().info('telegram.bot_started');