feat(feishu): extract embedded video/media from post (rich text) messages (#21786)

* feat(feishu): extract embedded video/media from post (rich text) messages

Previously, parsePostContent() only extracted embedded images (img tags)
from rich text posts, ignoring embedded video/audio (media tags). Users
sending post messages with embedded videos would not have the media
downloaded or forwarded to the agent.

Changes:
- Extend parsePostContent() to also collect media tags with file_key
- Return new mediaKeys array alongside existing imageKeys
- Update resolveFeishuMediaList() to download embedded media files
  from post messages using the messageResource API
- Add appropriate logging for embedded media discovery and download

* Feishu: keep embedded post media payloads type-safe

* Feishu: format post parser after media tag extraction

---------

Co-authored-by: laopuhuluwa <laopuhuluwa@users.noreply.github.com>
Co-authored-by: Tak Hoffman <781889+Takhoffman@users.noreply.github.com>

extensions/feishu/src/bot.test.ts

@@ -682,6 +682,60 @@ describe("handleFeishuMessage command authorization", () => {
     );
   });
 
+  it("downloads embedded media tags from post messages as files", async () => {
+    mockShouldComputeCommandAuthorized.mockReturnValue(false);
+
+    const cfg: ClawdbotConfig = {
+      channels: {
+        feishu: {
+          dmPolicy: "open",
+        },
+      },
+    } as ClawdbotConfig;
+
+    const event: FeishuMessageEvent = {
+      sender: {
+        sender_id: {
+          open_id: "ou-sender",
+        },
+      },
+      message: {
+        message_id: "msg-post-media",
+        chat_id: "oc-dm",
+        chat_type: "p2p",
+        message_type: "post",
+        content: JSON.stringify({
+          title: "Rich text",
+          content: [
+            [
+              {
+                tag: "media",
+                file_key: "file_post_media_payload",
+                file_name: "embedded.mov",
+              },
+            ],
+          ],
+        }),
+      },
+    };
+
+    await dispatchMessage({ cfg, event });
+
+    expect(mockDownloadMessageResourceFeishu).toHaveBeenCalledWith(
+      expect.objectContaining({
+        messageId: "msg-post-media",
+        fileKey: "file_post_media_payload",
+        type: "file",
+      }),
+    );
+    expect(mockSaveMediaBuffer).toHaveBeenCalledWith(
+      expect.any(Buffer),
+      "video/mp4",
+      "inbound",
+      expect.any(Number),
+    );
+  });
+
   it("includes message_id in BodyForAgent on its own line", async () => {
     mockShouldComputeCommandAuthorized.mockReturnValue(false);