feat: Add --max-depth option and safe symlink handling (v1.2.0)

## Neue Features

- **--max-depth N**: Begrenzt Rekursionstiefe auf N Ebenen (erfordert -r)
  - Nützlich für sehr tiefe Verzeichnisbäume (z.B. node_modules)
  - Verhindert unnötige Traversierung tiefer Strukturen

- **Explizites Symlink-Handling**:
  - Standard: Symlinks werden komplett übersprungen (sicher)
  - Mit --special: Nur Symlink-Namen werden bereinigt, Ziel bleibt unangetastet
  - follow_links(false) explizit gesetzt zur Vermeidung von Endlosschleifen
  - Verhindert unbeabsichtigte Änderungen außerhalb des Zielverzeichnisses

- **Verbose Symlink-Logging**: Zeigt mit -v welche Symlinks übersprungen werden

## Tests

- 5 neue Integration-Tests hinzugefügt:
  - test_max_depth_option
  - test_max_depth_requires_recursive
  - test_symlinks_default_behavior (Unix only)
  - test_symlinks_with_special_flag (Unix only)
  - test_symlinks_not_followed (Unix only)

- Alle 30 Tests bestehen (25 bestehende + 5 neue)

## Dokumentation

- README.md: Neue Beispiele und "Symlink Behavior" Sektion
- CHANGELOG.md: v1.2.0 Eintrag mit allen Änderungen
- man/ntu.1: --max-depth Option und SYMLINK BEHAVIOR Sektion
- CLAUDE.md: Aktualisierte Code-Architektur Dokumentation

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

man/ntu.1

@@ -1,4 +1,4 @@
-.TH NTU 1 "2025-02-10" "NameToUnix 1.1.0" "User Commands"
+.TH NTU 1 "2025-02-12" "NameToUnix 1.2.0" "User Commands"
 .SH NAME
 ntu \- sanitize file and directory names to Unix conventions
 .SH SYNOPSIS
@@ -21,6 +21,9 @@ like .tar.gz, and handles hidden files correctly.
 .BR \-r ", " \-\-recursive
 Process directories recursively (default: only immediate children)
 .TP
+.BR \-\-max\-depth " \fIN\fR"
+Limit recursion to N levels deep (requires \fB\-r\fR). Useful for processing only a few levels of a deep directory tree (e.g., limiting node_modules traversal).
+.TP
 .BR \-s ", " \-\-sequence " \fINAME\fR"
 Use a specific transformation sequence. Available sequences: default, lower, upper, minimal, utf-8. Use \fB\-L\fR to list all sequences.
 .TP
@@ -153,6 +156,28 @@ List all available sequences:
 .TP
 List sequences with details:
 .B ntu \-L \-v
+.TP
+Limit recursion depth to 3 levels:
+.B ntu \-r \-\-max\-depth 3 /path/to/files
+.TP
+Process symlink names (but don't follow them):
+.B ntu \-r \-\-special /path/to/files
+.SH SYMLINK BEHAVIOR
+By default, \fBntu\fR does not process symbolic links:
+.IP \(bu 2
+Symlinks are skipped (not renamed, not followed)
+.IP \(bu 2
+Prevents unintended changes outside the target directory
+.IP \(bu 2
+No risk of infinite loops from circular symlinks
+.PP
+With the \fB\-\-special\fR flag:
+.IP \(bu 2
+Symlink names are sanitized (e.g., "link to file" \(-> "link_to_file")
+.IP \(bu 2
+Symlinks are still not followed (targets remain unchanged)
+.IP \(bu 2
+Safe: only the link itself is renamed, not what it points to
 .SH CONFIGURATION
 .B ntu
 looks for configuration files in the following locations (in order):