feat(channels): emit line and zalo binary attachment fallback notices

src/channels/zalo/adapter.test.ts

@@ -81,9 +81,11 @@ describe('ZaloAdapter', () => {
       ],
     });
 
-    expect(mockFetch).toHaveBeenCalledTimes(2);
+    expect(mockFetch).toHaveBeenCalledTimes(3);
     const secondBody = JSON.parse(String(mockFetch.mock.calls[1]?.[1]?.body ?? '{}'));
+    const thirdBody = JSON.parse(String(mockFetch.mock.calls[2]?.[1]?.body ?? '{}'));
     expect(secondBody.message?.text).toBe('file.txt: https://example.com/file.txt');
+    expect(thirdBody.message?.text).toBe('[Zalo] Binary attachment not uploaded yet: attachment (application/pdf).');
     expect(warnSpy).toHaveBeenCalledWith('Zalo: skipping attachment data (application/pdf) — upload not implemented');
     warnSpy.mockRestore();
   });