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

CLAUDE.md

@@ -20,7 +20,7 @@ python -m py_compile src/daemon_boyfriend/**/*.py
 
 ## Architecture
 
-This is a Discord bot with AI chat (multi-provider) and SearXNG web search.
+This is a Discord bot that responds to @mentions with AI-generated responses (multi-provider support).
 
 ### Provider Pattern
 The AI system uses a provider abstraction pattern:
@@ -30,10 +30,8 @@ The AI system uses a provider abstraction pattern:
 - OpenRouter uses OpenAI's client with a different base URL
 
 ### Cog System
-Discord commands are organized as cogs in `cogs/`:
-- `ai_chat.py` - `/chat` command and `@mention` handler (primary user interaction)
-- `search.py` - `/search` and `/image` commands using SearXNG
-- `admin.py` - `/status`, `/help`, `/ping`, `/provider` commands
+Discord functionality is in `cogs/`:
+- `ai_chat.py` - `@mention` handler (responds when bot is mentioned)
 
 Cogs are auto-loaded by `bot.py` from the `cogs/` directory.
 
@@ -42,12 +40,9 @@ All config flows through `config.py` using pydantic-settings. The `settings` sin
 
 ### Key Design Decisions
 - `ConversationManager` stores per-user chat history in memory with configurable max length
-- `RateLimiter` tracks per-user rate limits using timestamps in a dict
 - Long AI responses are split via `split_message()` in `ai_chat.py` to respect Discord's 2000 char limit
-- The bot responds to @mentions via `on_message` listener, not just slash commands
+- The bot responds only to @mentions via `on_message` listener
 
 ## Environment Variables
 
 Required: `DISCORD_TOKEN`, plus one of `OPENAI_API_KEY`, `OPENROUTER_API_KEY`, or `ANTHROPIC_API_KEY` depending on `AI_PROVIDER` setting.
-
-Set `DISCORD_GUILD_ID` for instant slash command sync during development (otherwise global sync takes up to 1 hour).