i18n: migrate all German text to English

Enforce the repo convention that committed text is English.
Translates ABOUTME headers, code comments, log/error messages,
shell prompts, and documentation across all files.
CLAUDE.md files remain in German per policy.

README.md

@@ -1,49 +1,49 @@
 # Moonarch
 
-Reproduzierbares Arch-Linux-Setup mit Niri (Wayland Compositor), greetd/moongreet, Catppuccin Mocha Theming und durchgehender Automatisierung.
+Reproducible Arch Linux setup with Niri (Wayland compositor), greetd/moongreet, Catppuccin Mocha theming and full automation.
 
-## Schnellstart
+## Quick Start
 
-### Variante A: Config im Live-System herunterladen
+### Option A: Download config in the live system
 
-1. [Arch ISO](https://archlinux.org/download/) auf USB flashen und davon booten
-2. Im Live-System:
+1. Flash the [Arch ISO](https://archlinux.org/download/) to USB and boot from it
+2. In the live system:
    ```bash
    curl -O https://gitea.moonarch.de/nevaforget/moonarch/raw/branch/main/config/user_configuration.json
    archinstall --config user_configuration.json
    ```
-3. Disk + Kernel interaktiv waehlen, Rest kommt aus der Config
+3. Choose disk + kernel interactively, the rest comes from the config
 
-### Variante B: Config auf den USB-Stick legen (Ventoy)
+### Option B: Place config on USB stick (Ventoy)
 
-1. [Ventoy](https://www.ventoy.net/) auf USB installieren
-2. Arch ISO und `user_configuration.json` auf die Ventoy-Partition kopieren
-3. Davon booten, dann:
+1. Install [Ventoy](https://www.ventoy.net/) on USB
+2. Copy the Arch ISO and `user_configuration.json` to the Ventoy partition
+3. Boot from it, then:
    ```bash
    archinstall --config /run/media/ventoy/user_configuration.json
    ```
 
-### Nach archinstall
+### After archinstall
 
-1. Reboot — das Repo liegt bereits in `/opt/moonarch` (via custom-commands)
-2. Einloggen, dann:
+1. Reboot — the repo is already in `/opt/moonarch` (via custom-commands)
+2. Log in, then:
    ```bash
    /opt/moonarch/scripts/post-install.sh
    ```
-3. Nochmal rebooten — fertig
+3. Reboot again — done
 
-## Struktur
+## Structure
 
 ```
-config/          archinstall-Konfiguration
-packages/        Paketlisten (official.txt + aur.txt)
-scripts/         Post-Install, Update, Theme-Installer
+config/          archinstall configuration
+packages/        Package lists (official.txt + aur.txt)
+scripts/         Post-install, update, theme installer
 defaults/
-  bin/           moonarch-* Helper-Scripts (/usr/local/bin/)
-  xdg/           XDG-Defaults (/etc/xdg/)
-  shell/         Zsh-Konfiguration
-  etc/           greetd + moongreet Konfiguration
-  backgrounds/   Default-Wallpaper
+  bin/           moonarch-* helper scripts (/usr/local/bin/)
+  xdg/           XDG defaults (/etc/xdg/)
+  shell/         Zsh configuration
+  etc/           greetd + moongreet configuration
+  backgrounds/   Default wallpaper
 ```
 
 ## Update
@@ -52,7 +52,7 @@ defaults/
 moonarch-update
 ```
 
-Aktualisiert Repo, Systempakete, fehlende Pakete und Defaults — alles interaktiv mit Bestaetigungen.
+Updates repo, system packages, missing packages and defaults — all interactive with confirmations.
 
 ## Stack