feishu extension: tighten reply target fallback semantics

extensions/feishu/src/outbound.test.ts

@@ -155,6 +155,26 @@ describe("feishuOutbound.sendText local-image auto-convert", () => {
       }),
     );
   });
+
+  it("falls back to threadId when replyToId is empty on sendText", async () => {
+    await sendText({
+      cfg: {} as any,
+      to: "chat_1",
+      text: "hello",
+      replyToId: " ",
+      threadId: "om_thread_2",
+      accountId: "main",
+    } as any);
+
+    expect(sendMessageFeishuMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        to: "chat_1",
+        text: "hello",
+        replyToMessageId: "om_thread_2",
+        accountId: "main",
+      }),
+    );
+  });
 });
 
 describe("feishuOutbound.sendMedia renderMode", () => {
@@ -216,5 +236,13 @@ describe("feishuOutbound.sendMedia renderMode", () => {
         accountId: "main",
       }),
     );
+    expect(sendMessageFeishuMock).toHaveBeenCalledWith(
+      expect.objectContaining({
+        to: "chat_1",
+        text: "caption",
+        replyToMessageId: "om_thread_1",
+        accountId: "main",
+      }),
+    );
   });
 });

extensions/feishu/src/outbound.ts

@@ -47,11 +47,14 @@ function resolveReplyToMessageId(params: {
   replyToId?: string | null;
   threadId?: string | number | null;
 }): string | undefined {
-  const replyTarget = params.replyToId ?? params.threadId;
-  if (replyTarget == null) {
+  const replyToId = params.replyToId?.trim();
+  if (replyToId) {
+    return replyToId;
+  }
+  if (params.threadId == null) {
     return undefined;
   }
-  const trimmed = String(replyTarget).trim();
+  const trimmed = String(params.threadId).trim();
   return trimmed || undefined;
 }