Refactor: remove unused cogs and services, simplify architecture

- Remove admin.py and search.py cogs
- Remove searxng.py service and rate_limiter.py utility
- Update bot.py, ai_chat.py, config.py, and ai_service.py
- Update documentation and docker-compose.yml

src/daemon_boyfriend/services/__init__.py

@@ -3,14 +3,10 @@
 from .ai_service import AIService
 from .conversation import ConversationManager
 from .providers import AIResponse, Message
-from .searxng import SearchResponse, SearchResult, SearXNGService
 
 __all__ = [
     "AIService",
     "AIResponse",
     "Message",
     "ConversationManager",
-    "SearXNGService",
-    "SearchResponse",
-    "SearchResult",
 ]