fix(channels): forward line and zalo URL attachments

src/channels/line/adapter.test.ts

@@ -74,6 +74,56 @@ describe('LineAdapter', () => {
     expect(mockFetch.mock.calls[0]?.[0]).toBe('https://api.line.me/v2/bot/message/push');
   });
 
+  it('send emits URL attachments and warns for binary attachments', async () => {
+    const warnSpy = vi.spyOn(console, 'warn').mockImplementation(() => {});
+    const adapter = new LineAdapter({
+      channelAccessToken: 'token',
+      channelSecret: 'secret',
+    });
+    await adapter.connect();
+    mockFetch.mockResolvedValue({
+      ok: true,
+      status: 200,
+      text: async () => '',
+    } as Response);
+
+    await adapter.send('U123', {
+      text: 'hello line',
+      attachments: [
+        { mimeType: 'text/plain', url: 'https://example.com/file.txt', filename: 'file.txt' },
+        { mimeType: 'image/png', data: 'aGVsbG8=' },
+      ],
+    });
+
+    expect(mockFetch).toHaveBeenCalledTimes(2);
+    const secondBody = JSON.parse(String(mockFetch.mock.calls[1]?.[1]?.body ?? '{}'));
+    expect(secondBody.messages?.[0]?.text).toBe('file.txt: https://example.com/file.txt');
+    expect(warnSpy).toHaveBeenCalledWith('LINE: skipping attachment data (image/png) — upload not implemented');
+    warnSpy.mockRestore();
+  });
+
+  it('send delivers URL attachment even when text is empty', async () => {
+    const adapter = new LineAdapter({
+      channelAccessToken: 'token',
+      channelSecret: 'secret',
+    });
+    await adapter.connect();
+    mockFetch.mockResolvedValue({
+      ok: true,
+      status: 200,
+      text: async () => '',
+    } as Response);
+
+    await adapter.send('U123', {
+      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.messages?.[0]?.text).toBe('file.txt: https://example.com/file.txt');
+  });
+
   it('handleRequest validates signature and dispatches text event', async () => {
     const adapter = new LineAdapter({
       channelAccessToken: 'token',