Add deduplication and auto-name for subscriptions

- Config: add_subscription returns None on duplicate (same src, filter, dst)
- Bot: resolve chat titles via get_entity, name rule as
  "src -> dst (filter_value)"; show duplicate message instead of adding

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

src/bot/bot.py

@@ -63,7 +63,7 @@ class Bot():
         async def onMessageSub(event):
             if not self.__is_admin(event.sender_id):
                 raise events.StopPropagation
-            reply = self.__handle_sub_command(event.message.text or "")
+            reply = await self.__handle_sub_command(event.message.text or "")
             await event.reply(reply)
             await self.__bot.send_read_acknowledge(event.chat_id, event.message)
             raise events.StopPropagation
@@ -116,7 +116,7 @@ class Bot():
     def __is_admin(self, user_id) -> bool:
         return user_id == self.__owner_id or user_id in self.__admin_ids
 
-    def __handle_sub_command(self, text: str) -> str:
+    async def __handle_sub_command(self, text: str) -> str:
         parts = text.strip().split()
         if len(parts) < 2:
             return self.__sub_help()
@@ -135,9 +135,13 @@ class Bot():
                 if ftype not in ('contain', 'regexp'):
                     return "filter type must be 'contain' or 'regexp'"
                 value = tokens[5]
-                rule = self.__config.add_subscription(src, ftype, value, dst)
-                return "Added #{0}: {1} [{2}] '{3}' -> {4}".format(
-                    rule['id'], src, ftype, value, dst)
+                src_title = await self.__get_chat_title(src)
+                dst_title = await self.__get_chat_title(dst)
+                name = "{0} -> {1} ({2})".format(src_title, dst_title, value)
+                rule = self.__config.add_subscription(src, ftype, value, dst, name=name)
+                if rule is None:
+                    return "Already exists: {0} [{1}] '{2}' -> {3}".format(src, ftype, value, dst)
+                return "Added #{0}: {1}".format(rule['id'], rule.get('name', ''))
             if cmd in ('del', 'rm', 'delete'):
                 sub_id = int(parts[2])
                 ok = self.__config.remove_subscription(sub_id)
@@ -154,6 +158,13 @@ class Bot():
             return self.__sub_help()
         return self.__sub_help()
 
+    async def __get_chat_title(self, chat_id: int) -> str:
+        try:
+            entity = await self.__bot.get_entity(chat_id)
+            return getattr(entity, 'title', None) or getattr(entity, 'username', None) or str(chat_id)
+        except Exception:
+            return str(chat_id)
+
     def __sub_list(self) -> str:
         subs = self.__config.list_subscriptions()
         if not subs:

src/settings/config.py

@@ -41,10 +41,15 @@ class Config():
         return result
 
     def add_subscription(self, src_chat_id: int, filter_type: str, filter_value: str,
-                         dst_chat_id: int, name: Optional[str] = None) -> dict:
+                         dst_chat_id: int, name: Optional[str] = None) -> Optional[dict]:
         with self.__lock:
             on_message = self.__config.setdefault('onMessage', {})
             rules = on_message.setdefault(str(src_chat_id), [])
+            for existing in rules:
+                if (existing.get('filter', {}).get('type') == filter_type and
+                        existing.get('filter', {}).get('value') == filter_value and
+                        existing.get('action', {}).get('chatId') == dst_chat_id):
+                    return None
             rule = {
                 'id': self.__next_id(),
                 'enabled': True,