Implement sequences feature v1.1.0

- Add -s/--sequence option to select transformation sequences
- Add -L flag to list all available sequences
- Implement 5 hardcoded sequences: default, lower, upper, minimal, utf-8
- Refactor clean_filename() to support sequence-based transformations
- Update all tests to pass sequence parameter (25 tests passing)
- Add 8 new integration tests for sequence functionality
- Update documentation (README, CHANGELOG, manpage)
- Update shell completions (bash, zsh, fish)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

completions/_ntu

@@ -8,6 +8,8 @@ _ntu() {
 
     _arguments -C \
         '(-r --recursive)'{-r,--recursive}'[Process directories recursively]' \
+        '(-s --sequence)'{-s,--sequence}'[Use transformation sequence]:sequence:(default lower upper minimal utf-8)' \
+        '-L[List available sequences]' \
         '--conf[Use specific configuration file]:config file:_files' \
         '(-n --dry-run --no-changes)'{-n,--dry-run,--no-changes}'[Only preview changes without renaming]' \
         '(-q --quiet)'{-q,--quiet}'[Suppress output]' \