refactor: remove startup announcement logic from on_startup function

bot.py

@@ -405,24 +405,6 @@ def init_counters(existing: Dict[str, int], config: Dict[str, Any]) -> Dict[str,
 
 async def on_startup(app):
     logger.info("Bot gestartet und bereit.")
-    announce_ids = os.environ.get("STARTUP_ANNOUNCE_CHAT_IDS")
-    if announce_ids:
-        ids = []
-        for raw in announce_ids.split(','):
-            raw = raw.strip()
-            if not raw:
-                continue
-            try:
-                ids.append(int(raw))
-            except ValueError:
-                logger.warning("Kann Chat ID %s nicht in int umwandeln", raw)
-        if ids:
-            me = await app.bot.get_me()
-            for cid in ids:
-                try:
-                    await app.bot.send_message(cid, f"🤖 {me.first_name} ist bereit. Nutze /help für Befehle.")
-                except Exception as e:
-                    logger.warning("Konnte Startup-Nachricht an %s nicht senden: %s", cid, e)
 
 
 def main():