feat: migrate runtime backend to node server

tools/Caddyfile.dev

@@ -0,0 +1,21 @@
+{
+	auto_https off
+}
+
+:8080 {
+	root * {$CADDY_SITE_ROOT}
+
+	handle /api/* {
+		reverse_proxy {$CADDY_API_UPSTREAM}
+	}
+
+	handle /healthz {
+		respond "ok" 200
+	}
+
+	handle {
+		encode gzip zstd
+		try_files {path} /index.html
+		file_server
+	}
+}