Design configuration merging algorithm

**Summary**: Create a robust algorithm for merging base configuration files with environment-specific overrides, including conflict resolution and precedence rules.

**Acceptance Criteria**:
- [ ] Configuration merging strategy with clear precedence rules (environment-specific overrides base)
- [ ] Deep merge support for nested YAML structures
- [ ] Array and list merging strategies (replace, append, merge)
- [ ] Conflict detection and resolution mechanisms
- [ ] Performance optimization for large configuration files
- [ ] Comprehensive test coverage for all merging scenarios