fix(channels): forward line and zalo URL attachments

src/channels/zalo/adapter.test.ts

@@ -63,6 +63,50 @@ describe('ZaloAdapter', () => {
     expect(String(mockFetch.mock.calls[0]?.[0])).toContain('/v3.0/oa/message/cs');
   });
 
+  it('send emits URL attachments and warns for binary attachments', async () => {
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const adapter = new ZaloAdapter({ oaAccessToken: 'token' });
+    await adapter.connect();
+    mockFetch.mockResolvedValue({
+      ok: true,
+      status: 200,
+      text: async () => '',
+    } as Response);
+
+    await adapter.send('uid-1', {
+      text: 'hello zalo',
+      attachments: [
+        { mimeType: 'text/plain', url: 'https://example.com/file.txt', filename: 'file.txt' },
+        { mimeType: 'application/pdf', data: 'aGVsbG8=' },
+      ],
+    });
+
+    expect(mockFetch).toHaveBeenCalledTimes(2);
+    const secondBody = JSON.parse(String(mockFetch.mock.calls[1]?.[1]?.body ?? '{}'));
+    expect(secondBody.message?.text).toBe('file.txt: https://example.com/file.txt');
+    expect(warnSpy).toHaveBeenCalledWith('Zalo: skipping attachment data (application/pdf) — upload not implemented');
+    warnSpy.mockRestore();
+  });
+
+  it('send delivers URL attachment even when text is empty', async () => {
+    const adapter = new ZaloAdapter({ oaAccessToken: 'token' });
+    await adapter.connect();
+    mockFetch.mockResolvedValue({
+      ok: true,
+      status: 200,
+      text: async () => '',
+    } as Response);
+
+    await adapter.send('uid-1', {
+      text: ' ',
+      attachments: [{ mimeType: 'text/plain', url: 'https://example.com/file.txt', filename: 'file.txt' }],
+    });
+
+    expect(mockFetch).toHaveBeenCalledTimes(1);
+    const body = JSON.parse(String(mockFetch.mock.calls[0]?.[1]?.body ?? '{}'));
+    expect(body.message?.text).toBe('file.txt: https://example.com/file.txt');
+  });
+
   it('handleEvent emits inbound message', async () => {
     const adapter = new ZaloAdapter({ oaAccessToken: 'token', requireMention: false });
     const inbound: Array<{ channel: string; senderId: string; text: string }> = [];