feat(bot): enhance group chat handling and mention detection

- Updated bot to only respond in group chats when explicitly mentioned.
- Added mention detection using regex for "Claude" patterns and cleaned up the message text for processing.
- Improved help message to clarify usage in direct messages and group chats.

systems/x86_64-linux/mx/nextcloud-claude-bot/bot.py

@@ -11,6 +11,7 @@ import hmac
 import json
 import logging
 import os
+import re
 import subprocess
 from datetime import datetime
 from typing import Optional
@@ -209,15 +210,40 @@ async def handle_webhook(
     conversation_token = conversation.get("token", "")
     conversation_type = conversation.get("type", 0)
     
-    # Only respond to user messages in one-on-one chats (type 1)
+    # Only respond to user messages
     if actor_type != "users":
         log.info(f"Ignoring non-user actor: {actor_type}")
         return JSONResponse({"status": "ignored", "reason": "not a user message"})
-    
-    if conversation_type != 1:  # 1 = one-to-one
-        log.info(f"Ignoring non-DM conversation type: {conversation_type}")
-        return JSONResponse({"status": "ignored", "reason": "not a direct message"})
-    
+
+    # For group chats (type 2, 3, 4), only respond if bot is mentioned
+    # Type 1 = one-to-one, Type 2 = group, Type 3 = public, Type 4 = changelog
+    is_direct_message = conversation_type == 1
+
+    # Check for bot mention in message (Nextcloud uses @"Bot Name" format)
+    bot_mentioned = False
+    clean_message = message_text
+
+    # Look for mention patterns: @Claude or @"Claude"
+    mention_patterns = [
+        r'@"?Claude"?\s*',
+        r'@"?claude"?\s*',
+    ]
+
+    for pattern in mention_patterns:
+        if re.search(pattern, message_text, re.IGNORECASE):
+            bot_mentioned = True
+            clean_message = re.sub(pattern, '', message_text, flags=re.IGNORECASE).strip()
+            break
+
+    # In group chats, only respond if mentioned
+    if not is_direct_message and not bot_mentioned:
+        log.info(f"Ignoring message in group chat without mention")
+        return JSONResponse({"status": "ignored", "reason": "not mentioned in group chat"})
+
+    # Use clean message (without mention) for processing
+    if bot_mentioned:
+        message_text = clean_message
+
     # Check allowed users
     if ALLOWED_USERS and actor_id not in ALLOWED_USERS:
         log.warning(f"User {actor_id} not in allowed list")
@@ -253,6 +279,10 @@ async def handle_webhook(
 
 Schreib mir einfach eine Nachricht und ich antworte dir.
 
+**Nutzung:**
+• In Direktnachrichten: Einfach schreiben
+• In Gruppenchats: @Claude gefolgt von deiner Frage
+
 **Befehle:**
 • `/clear` oder `/reset` – Konversation zurücksetzen
 • `/help` oder `/hilfe` – Diese Hilfe anzeigen