Implement comprehensive rate limiting system and item spawn configuration

Major Features Added:
- Complete token bucket rate limiting for IRC commands and web interface
- Per-user rate tracking with category-based limits (Basic, Gameplay, Management, Admin, Web)
- Admin commands for rate limit management (\!rate_stats, \!rate_user, \!rate_unban, \!rate_reset)
- Automatic violation tracking and temporary bans with cleanup
- Global item spawn multiplier system with 75% spawn rate reduction
- Central admin configuration system (config.py)
- One-command bot startup script (start_petbot.sh)

Rate Limiting:
- Token bucket algorithm with burst capacity and refill rates
- Category limits: Basic (20/min), Gameplay (10/min), Management (5/min), Web (60/min)
- Graceful violation handling with user-friendly error messages
- Admin exemption and override capabilities
- Background cleanup of old violations and expired bans

Item Spawn System:
- Added global_spawn_multiplier to config/items.json for easy adjustment
- Reduced all individual spawn rates by 75% (multiplied by 0.25)
- Admins can fine-tune both global multiplier and individual item rates
- Game engine integration applies multiplier to all spawn calculations

Infrastructure:
- Single admin user configuration in config.py
- Enhanced startup script with dependency management and verification
- Updated documentation and help system with rate limiting guide
- Comprehensive test suite for rate limiting functionality

Security:
- Rate limiting protects against command spam and abuse
- IP-based tracking for web interface requests
- Proper error handling and status codes (429 for rate limits)

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

requirements.txt

@@ -1,4 +1,44 @@
+# PetBot Requirements
+# Core dependencies for IRC bot functionality
+
+# IRC client library for connecting to IRC servers
 irc>=20.3.0
+
+# Async SQLite database interface for database operations
 aiosqlite>=0.19.0
+
+# Environment variable loading (for configuration)
 python-dotenv>=1.0.0
-asyncio
+
+# HTTP client for web interface testing and rate limiting tests
+aiohttp>=3.8.0
+
+# Note: The following are part of Python's standard library and don't need installation:
+# - asyncio (async programming)
+# - sqlite3 (synchronous SQLite operations)
+# - json (JSON data handling)
+# - socket (network communication)
+# - threading (thread management)
+# - time (time operations)
+# - os (operating system interface)
+# - sys (system parameters)
+# - logging (logging framework)
+# - pathlib (path handling)
+# - urllib.parse (URL parsing)
+# - datetime (date/time handling)
+# - typing (type annotations)
+# - enum (enumerations)
+# - abc (abstract base classes)
+# - importlib (import utilities)
+# - signal (signal handling)
+# - shutil (file operations)
+# - gzip (compression)
+# - tempfile (temporary files)
+# - http.server (HTTP server)
+# - random (random numbers)
+
+# Development and testing dependencies (optional)
+# These are not required for basic bot operation but useful for development:
+# pytest>=7.0.0
+# black>=22.0.0
+# flake8>=4.0.0