- Fix memory leak in delta_deserialize() on BLOCK_MATCH error path
- Fix memory leak on malloc failure for literal data
- Add port range validation (1-65535) for -p/--port and --server-port
- Restore -V/--version flag with usage text
- Use MAX_DATA_PAYLOAD_SIZE consistently (remove local MAX_DATA_SIZE)
- Fix integer truncation in config_send/config_receive for delta_block_size
- Add log messages for malloc failures
- Extract config_set_defaults() helper to eliminate duplication
- Add 10 new CLI tests for argument parsing