Initial commit: 50 shell-script generators with web UI

- 8 categories / 50 generators covering middleware, databases, runtimes,
  systemd services, system tools, network, monitoring, security
- VNC supports XFCE / GNOME / KDE Plasma / MATE / LXQt desktops
- Node.js versions 18-26 (incl. current LTS 24 Krypton and current 26)
- Live preview, copy / download / multi-script bundle in web UI
- Distro-aware (Ubuntu/Debian/CentOS/RHEL/Rocky/Alma/Fedora)
- All 50 generators pass bash -n syntax check
- Zero pip dependencies (Flask stdlib only)

start.sh

@@ -0,0 +1,9 @@
+#!/usr/bin/env bash
+# shell-gen - Linux shell script generator web UI
+# Run on host as a foreground process (development) or via systemd (production).
+set -euo pipefail
+cd "$(dirname "$0")"
+export PORT="${PORT:-5099}"
+export FLASK_ENV="${FLASK_ENV:-production}"
+echo "Starting shell-gen on port $PORT (PID $$)..."
+exec python3 app.py