- Add toml and home dependencies
- Create comprehensive config module with validation
- Add Config struct with server, database, logging, performance sections
- Support config file loading with CLI override precedence
- Update CLI to accept --config option
- Update main.rs to use configuration system
- Add default buffdb.toml with examples
- Update README with configuration documentation
- Maintain backward compatibility with existing CLI args

Configuration precedence:
1. CLI arguments (highest)
2. Config file
3. Default values (lowest)

Features:
- TOML format with all standard configuration options
- Automatic config file discovery
- Validation and error handling
- Performance tuning options