feat: config file parser + writer utilities with full test coverage (Tasks 4.1, 4.2)
- Fail2BanConfigParser class: merge order, include directives (before/after),
variable interpolation %(var)s, split_multiline, ordered_conf_files
- config_writer: write_local_override, remove_local_key, delete_local_file
with atomic writes (os.replace), per-file threading locks, .local-only guard
- 79 tests in tests/test_utils/ (all passing)
- mypy --strict: 60 source files, 0 errors
- ruff: all checks passed
Lukas
6e4797d71e