feat(feishu): add done emoji support for reaction lifecycle (#2899)

* feat(feishu): add done emoji support for reaction lifecycle

* feat(feishu): add done emoji support and update documentation

README.md

@@ -560,6 +560,8 @@ Uses **WebSocket** long connection — no public IP required.
       "verificationToken": "",
       "allowFrom": ["ou_YOUR_OPEN_ID"],
       "groupPolicy": "mention",
+      "reactEmoji": "OnIt",
+      "doneEmoji": "DONE",
       "streaming": true
     }
   }
@@ -570,6 +572,8 @@ Uses **WebSocket** long connection — no public IP required.
 > `encryptKey` and `verificationToken` are optional for Long Connection mode.
 > `allowFrom`: Add your open_id (find it in nanobot logs when you message the bot). Use `["*"]` to allow all users.
 > `groupPolicy`: `"mention"` (default — respond only when @mentioned), `"open"` (respond to all group messages). Private chats always respond.
+> `reactEmoji`: Emoji for "processing" status (default: `OnIt`). See [available emojis](https://open.larkoffice.com/document/server-docs/im-v1/message-reaction/emojis-introduce).
+> `doneEmoji`: Optional emoji for "completed" status (e.g., `DONE`, `OK`, `HEART`). When set, bot adds this reaction after removing `reactEmoji`.
 
 **3. Run**