feat: CI/CD, Bash-Completion und README-Verbesserungen

- GitHub Actions CI Pipeline (Tests, Clippy, Format-Checks)
- GitHub Actions Release Pipeline (Multi-Platform Builds)
- Bash-Completion Script für Shell-Autovervollständigung
- Zsh-Completion Script (_ntu)
- README Badges (CI, Release, Version, License)
- Installationsanleitung für Pre-built Binaries
- Alte build.yaml entfernt (ersetzt durch moderne ci.yml)

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

completions/_ntu

@@ -0,0 +1,22 @@
+#compdef ntu
+
+# Zsh completion for ntu (NameToUnix)
+
+_ntu() {
+    local curcontext="$curcontext" state line
+    typeset -A opt_args
+
+    _arguments -C \
+        '(-n --dry-run --no-changes)'{-n,--dry-run,--no-changes}'[Only preview changes without renaming]' \
+        '(-q --quiet)'{-q,--quiet}'[Suppress output]' \
+        '(-f --force)'{-f,--force}'[Overwrite existing files]' \
+        '*'{-e,--exclude}'[Exclude pattern]:pattern:' \
+        '(-v --verbose)'{-v,--verbose}'[Verbose debug output]' \
+        '--modify-root[Also rename root directory]' \
+        '--special[Process symlinks and special files]' \
+        '(-h --help)'{-h,--help}'[Print help]' \
+        '(-V --version)'{-V,--version}'[Print version]' \
+        '*:path:_files'
+}
+
+_ntu "$@"