feat(feishu): make reaction emoji configurable

Replace hardcoded THUMBSUP with configurable react_emoji field
in FeishuConfig, consistent with SlackConfig.react_emoji pattern.

Default remains THUMBSUP for backward compatibility.

nanobot/channels/feishu.py

@@ -692,7 +692,7 @@ class FeishuChannel(BaseChannel):
             msg_type = message.message_type
 
             # Add reaction
-            await self._add_reaction(message_id, "THUMBSUP")
+            await self._add_reaction(message_id, self.config.react_emoji)
 
             # Parse content
             content_parts = []

nanobot/config/schema.py

@@ -42,6 +42,7 @@ class FeishuConfig(Base):
     encrypt_key: str = ""  # Encrypt Key for event subscription (optional)
     verification_token: str = ""  # Verification Token for event subscription (optional)
     allow_from: list[str] = Field(default_factory=list)  # Allowed user open_ids
+    react_emoji: str = "THUMBSUP"  # Emoji type for message reactions (e.g. THUMBSUP, OK, DONE, SMILE)
 
 
 class DingTalkConfig(Base):