feat(slack): update reaction emoji on task completion

Remove the in-progress reaction (reactEmoji) and optionally add a
done reaction (doneEmoji) when the final response is sent, so users
get visual feedback that processing has finished.

Signed-off-by: Sihyeon Jang <sihyeon.jang@navercorp.com>

nanobot/channels/slack.py

@@ -136,6 +136,12 @@ class SlackChannel(BaseChannel):
                     )
                 except Exception as e:
                     logger.error("Failed to upload file {}: {}", media_path, e)
+
+            # Update reaction emoji when the final (non-progress) response is sent
+            if not (msg.metadata or {}).get("_progress"):
+                event = slack_meta.get("event", {})
+                await self._update_react_emoji(msg.chat_id, event.get("ts"))
+
         except Exception as e:
             logger.error("Error sending Slack message: {}", e)
 
@@ -233,6 +239,28 @@ class SlackChannel(BaseChannel):
         except Exception:
             logger.exception("Error handling Slack message from {}", sender_id)
 
+    async def _update_react_emoji(self, chat_id: str, ts: str | None) -> None:
+        """Remove the in-progress reaction and optionally add a done reaction."""
+        if not self._web_client or not ts:
+            return
+        try:
+            await self._web_client.reactions_remove(
+                channel=chat_id,
+                name=self.config.react_emoji,
+                timestamp=ts,
+            )
+        except Exception as e:
+            logger.debug("Slack reactions_remove failed: {}", e)
+        if self.config.done_emoji:
+            try:
+                await self._web_client.reactions_add(
+                    channel=chat_id,
+                    name=self.config.done_emoji,
+                    timestamp=ts,
+                )
+            except Exception as e:
+                logger.debug("Slack done reaction failed: {}", e)
+
     def _is_allowed(self, sender_id: str, chat_id: str, channel_type: str) -> bool:
         if channel_type == "im":
             if not self.config.dm.enabled:

nanobot/config/schema.py

@@ -13,7 +13,6 @@ class Base(BaseModel):
 
     model_config = ConfigDict(alias_generator=to_camel, populate_by_name=True)
 
-
 class ChannelsConfig(Base):
     """Configuration for chat channels.