fix(telegram): draft stream preview not threaded when replyToMode is on (#17880) (#17928)

Merged via /review-pr -> /prepare-pr -> /merge-pr.

Prepared head SHA: cfd4181a23
Co-authored-by: yinghaosang <261132136+yinghaosang@users.noreply.github.com>
Co-authored-by: obviyus <22031114+obviyus@users.noreply.github.com>
Reviewed-by: @obviyus

src/telegram/draft-stream.test.ts

@@ -113,4 +113,82 @@ describe("createTelegramDraftStream", () => {
 
     expect(api.deleteMessage).toHaveBeenCalledWith(123, 17);
   });
+
+  it("includes reply_to_message_id in initial sendMessage when replyToMessageId is set", async () => {
+    const api = {
+      sendMessage: vi.fn().mockResolvedValue({ message_id: 42 }),
+      editMessageText: vi.fn().mockResolvedValue(true),
+      deleteMessage: vi.fn().mockResolvedValue(true),
+    };
+    const stream = createTelegramDraftStream({
+      // oxlint-disable-next-line typescript/no-explicit-any
+      api: api as any,
+      chatId: 123,
+      replyToMessageId: 999,
+    });
+
+    stream.update("Hello");
+    await vi.waitFor(() =>
+      expect(api.sendMessage).toHaveBeenCalledWith(123, "Hello", { reply_to_message_id: 999 }),
+    );
+  });
+
+  it("includes both reply_to_message_id and message_thread_id when both are set", async () => {
+    const api = {
+      sendMessage: vi.fn().mockResolvedValue({ message_id: 42 }),
+      editMessageText: vi.fn().mockResolvedValue(true),
+      deleteMessage: vi.fn().mockResolvedValue(true),
+    };
+    const stream = createTelegramDraftStream({
+      // oxlint-disable-next-line typescript/no-explicit-any
+      api: api as any,
+      chatId: 123,
+      thread: { id: 99, scope: "forum" },
+      replyToMessageId: 555,
+    });
+
+    stream.update("Hello");
+    await vi.waitFor(() =>
+      expect(api.sendMessage).toHaveBeenCalledWith(123, "Hello", {
+        message_thread_id: 99,
+        reply_to_message_id: 555,
+      }),
+    );
+  });
+
+  it("passes undefined params when neither thread nor replyToMessageId is set", async () => {
+    const api = {
+      sendMessage: vi.fn().mockResolvedValue({ message_id: 42 }),
+      editMessageText: vi.fn().mockResolvedValue(true),
+      deleteMessage: vi.fn().mockResolvedValue(true),
+    };
+    const stream = createTelegramDraftStream({
+      // oxlint-disable-next-line typescript/no-explicit-any
+      api: api as any,
+      chatId: 123,
+    });
+
+    stream.update("Hello");
+    await vi.waitFor(() => expect(api.sendMessage).toHaveBeenCalledWith(123, "Hello", undefined));
+  });
+
+  it("includes reply_to_message_id even when thread resolves to general topic", async () => {
+    const api = {
+      sendMessage: vi.fn().mockResolvedValue({ message_id: 42 }),
+      editMessageText: vi.fn().mockResolvedValue(true),
+      deleteMessage: vi.fn().mockResolvedValue(true),
+    };
+    const stream = createTelegramDraftStream({
+      // oxlint-disable-next-line typescript/no-explicit-any
+      api: api as any,
+      chatId: 123,
+      thread: { id: 1, scope: "forum" },
+      replyToMessageId: 888,
+    });
+
+    stream.update("Hello");
+    await vi.waitFor(() =>
+      expect(api.sendMessage).toHaveBeenCalledWith(123, "Hello", { reply_to_message_id: 888 }),
+    );
+  });
 });