feat: Add safeWriteJson utility for atomic file operations

Implements a robust JSON file writing utility that:
- Prevents concurrent writes to the same file using in-memory locks
- Ensures atomic operations with temporary file and backup strategies
- Handles error cases with proper rollback mechanisms
- Cleans up temporary files even when operations fail
- Provides comprehensive test coverage for success and failure scenarios

Signed-off-by: Eric Wheeler <[email protected]>

Author: Eric Wheeler