feat(telegram): add message reactions on processing start/complete

Mirror the Discord reaction pattern for Telegram:
- 👀 (eyes) when message processing begins
- ✅ (check) on successful completion
- ❌ (cross) on failure

Controlled via TELEGRAM_REACTIONS env var or telegram.reactions
in config.yaml (enabled by default, like Discord).

Uses python-telegram-bot's Bot.set_message_reaction() API.
Failures are caught and logged at debug level so they never
break message processing.

gateway/config.py

@@ -582,6 +582,8 @@ def load_gateway_config() -> GatewayConfig:
                     if isinstance(frc, list):
                         frc = ",".join(str(v) for v in frc)
                     os.environ["TELEGRAM_FREE_RESPONSE_CHATS"] = str(frc)
+                if "reactions" in telegram_cfg and not os.getenv("TELEGRAM_REACTIONS"):
+                    os.environ["TELEGRAM_REACTIONS"] = str(telegram_cfg["reactions"]).lower()
 
             whatsapp_cfg = yaml_cfg.get("whatsapp", {})
             if isinstance(whatsapp_cfg, dict):

gateway/platforms/telegram.py

@@ -2673,3 +2673,57 @@ class TelegramAdapter(BasePlatformAdapter):
             auto_skill=topic_skill,
             timestamp=message.date,
         )
+
+    # ── Message reactions (processing lifecycle) ──────────────────────────
+
+    def _reactions_enabled(self) -> bool:
+        """Check if message reactions are enabled via config/env."""
+        return os.getenv("TELEGRAM_REACTIONS", "true").lower() not in ("false", "0", "no")
+
+    async def _set_reaction(self, chat_id: str, message_id: str, emoji: str) -> bool:
+        """Set a single emoji reaction on a Telegram message."""
+        if not self._bot:
+            return False
+        try:
+            await self._bot.set_message_reaction(
+                chat_id=int(chat_id),
+                message_id=int(message_id),
+                reaction=emoji,
+            )
+            return True
+        except Exception as e:
+            logger.debug("[%s] set_message_reaction failed (%s): %s", self.name, emoji, e)
+            return False
+
+    async def _remove_reaction(self, chat_id: str, message_id: str) -> bool:
+        """Remove all reactions from a Telegram message."""
+        if not self._bot:
+            return False
+        try:
+            await self._bot.set_message_reaction(
+                chat_id=int(chat_id),
+                message_id=int(message_id),
+                reaction=None,
+            )
+            return True
+        except Exception as e:
+            logger.debug("[%s] remove_reaction failed: %s", self.name, e)
+            return False
+
+    async def on_processing_start(self, event: MessageEvent) -> None:
+        """Add an in-progress reaction when message processing begins."""
+        if not self._reactions_enabled():
+            return
+        chat_id = getattr(event.source, "chat_id", None)
+        message_id = getattr(event, "message_id", None)
+        if chat_id and message_id:
+            await self._set_reaction(chat_id, message_id, "\U0001f440")
+
+    async def on_processing_complete(self, event: MessageEvent, success: bool) -> None:
+        """Swap the in-progress reaction for a final success/failure reaction."""
+        if not self._reactions_enabled():
+            return
+        chat_id = getattr(event.source, "chat_id", None)
+        message_id = getattr(event, "message_id", None)
+        if chat_id and message_id:
+            await self._set_reaction(chat_id, message_id, "\u2705" if success else "\u274c")