feat: direct VPS installer — Node.js 22 + Caddy + systemd, no Docker

Replaces the Docker-based install.sh with a direct-install approach:
- Docker cleanup: removes container, stops daemon, uninstalls packages
- Node.js 22 via NodeSource apt/rpm/pacman repos
- Caddy via Cloudsmith apt/COPR/pacman repos
- Clone, npm ci, npm run build, standalone output
- systemd unit (worst-scan-web.service) — user-level service, HOSTNAME=127.0.0.1
- Caddy reverse proxy on :80 → 127.0.0.1:3000
- deploy/ reference files for manual editing

~150-160 MB RAM total (vs ~300-400 MB with Docker) on 1GB VPS

deploy/Caddyfile

@@ -0,0 +1,7 @@
+# worst-scan-web — Caddy reverse proxy
+# Copy to /etc/caddy/Caddyfile or include from there.
+# Replace :80 with your domain for auto-HTTPS.
+
+:80 {
+    reverse_proxy 127.0.0.1:3000
+}