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.bash

@@ -7,10 +7,15 @@ _ntu_completion() {
     prev="${COMP_WORDS[COMP_CWORD-1]}"
 
     # All available options
-    opts="--recursive --conf --dry-run --no-changes --quiet --force --exclude --verbose --modify-root --special --no-color --help --version -r -n -q -f -e -v -h -V"
+    opts="--recursive --sequence --conf --dry-run --no-changes --quiet --force --exclude --verbose --modify-root --special --no-color --help --version -r -s -L -n -q -f -e -v -h -V"
 
     # Handle options that require arguments
     case "${prev}" in
+        -s|--sequence)
+            # Suggest available sequences
+            COMPREPLY=( $(compgen -W "default lower upper minimal utf-8" -- ${cur}) )
+            return 0
+            ;;
         -e|--exclude)
             # Suggest glob patterns
             COMPREPLY=( $(compgen -W '"*.tmp" "*.log" "*.bak" "*.swp" "*~"' -- ${cur}) )