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>

README.md

@@ -39,6 +39,27 @@ specified paths and their immediate children by default. Use the `-r` or
 # New (v1.x): ntu -r /path/to/files
 ```
 
+## Sequences
+
+Starting with v1.1.0, `ntu` supports transformation sequences similar to detox. Sequences control how filenames are transformed:
+
+- **default**: Standard transformation (umlauts→ASCII, spaces→underscores, remove special chars)
+- **lower**: Like default, but convert to lowercase
+- **upper**: Like default, but convert to UPPERCASE
+- **minimal**: Only replace spaces, keep UTF-8 characters
+- **utf-8**: UTF-8 friendly (keep umlauts, replace spaces, remove special chars)
+
+```bash
+# Use specific sequence
+ntu -s lower /path/to/files
+
+# List all available sequences
+ntu -L
+
+# List sequences with details
+ntu -L -v
+```
+
 ## Functions / Funktionen
 
 - Replaces spaces and special characters in file and directory names with underscores
@@ -146,6 +167,20 @@ ntu -r --modify-root /path/to/files
 # Combine options
 ntu --dry-run -r -v --special /path/to/files
 
+# Use lowercase sequence
+ntu -r -s lower /path/to/files
+
+# Minimal mode (only spaces, keep UTF-8)
+ntu -s minimal /path/to/files
+
+# UTF-8 friendly mode
+ntu -s utf-8 /path/to/files
+
+# List available sequences
+ntu -L
+
+# List sequences with details
+ntu -L -v
 ```
 
 **Note:** The following directories/files are automatically excluded:
@@ -185,6 +220,20 @@ ntu -r --modify-root /pfad/zu/dateien
 # Optionen kombinieren
 ntu --dry-run -r -v --special /pfad/zu/dateien
 
+# Kleinbuchstaben-Sequenz verwenden
+ntu -r -s lower /pfad/zu/dateien
+
+# Minimal-Modus (nur Leerzeichen, UTF-8 behalten)
+ntu -s minimal /pfad/zu/dateien
+
+# UTF-8 freundlicher Modus
+ntu -s utf-8 /pfad/zu/dateien
+
+# Verfügbare Sequenzen auflisten
+ntu -L
+
+# Sequenzen mit Details auflisten
+ntu -L -v
 ```
 
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