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

.env.example

@@ -1,33 +1,55 @@
+# ===========================================
 # Discord Configuration
+# ===========================================
+# Your Discord bot token (get it from https://discord.com/developers/applications)
 DISCORD_TOKEN=your_discord_bot_token_here
-DISCORD_GUILD_ID=                          # Optional: for faster command sync during development
 
+# ===========================================
 # AI Provider Configuration
+# ===========================================
 # Available providers: "openai", "openrouter", "anthropic"
 AI_PROVIDER=openai
+
+# Model to use (e.g., gpt-4o, gpt-4o-mini, claude-3-5-sonnet, etc.)
 AI_MODEL=gpt-4o
 
-# Provider API Keys (set the ones you use)
+# Provider API Keys (set the one you use)
 OPENAI_API_KEY=sk-xxx
 OPENROUTER_API_KEY=sk-or-xxx
 ANTHROPIC_API_KEY=sk-ant-xxx
 
-# AI Settings
+# Maximum tokens in AI response (100-4096)
 AI_MAX_TOKENS=1024
+
+# AI creativity/randomness (0.0 = deterministic, 2.0 = very creative)
 AI_TEMPERATURE=0.7
 
-# SearXNG Configuration
-SEARXNG_BASE_URL=http://localhost:8080
-SEARXNG_TIMEOUT=10
+# ===========================================
+# Bot Identity & Personality
+# ===========================================
+# The bot's name, used in the system prompt to tell the AI who it is
+BOT_NAME=My Bot
 
-# Rate Limiting
-RATE_LIMIT_MESSAGES=10                     # Messages per user per minute
-RATE_LIMIT_SEARCHES=5                      # Searches per user per minute
+# Personality traits that define how the bot responds (used in system prompt)
+BOT_PERSONALITY=helpful and friendly
 
-# Logging
-LOG_LEVEL=INFO
+# Message shown when someone mentions the bot without saying anything
+BOT_DESCRIPTION=I'm an AI assistant here to help you.
 
-# Bot Behavior
-BOT_NAME=Daemon Boyfriend
-BOT_PERSONALITY=helpful, witty, and slightly mischievous
+# Status message shown in Discord (displays as "Watching <BOT_STATUS>")
+BOT_STATUS=for mentions
+
+# Optional: Override the entire system prompt (leave commented to use auto-generated)
+# SYSTEM_PROMPT=You are a custom assistant...
+
+# ===========================================
+# Conversation Settings
+# ===========================================
+# Number of messages to remember per user (higher = more context, more tokens)
 MAX_CONVERSATION_HISTORY=20
+
+# ===========================================
+# Logging
+# ===========================================
+# Log level: DEBUG, INFO, WARNING, ERROR
+LOG_LEVEL=INFO