⬆️ chore: standardize on Node 24

- Dockerfile: node:22-alpine -> node:24-alpine
- package.json: add engines.node >=24

Verified: npm ci + npm test 25/25 pass, npm audit 0 vulns,
docker build succeeds, running 24-alpine image serves
/health -> {"status":"ok"} (HTTP 200).

Author: luiscosio

Dockerfile

@@ -1,4 +1,4 @@
-FROM node:22-alpine
+FROM node:24-alpine
 WORKDIR /app
 COPY package.json package-lock.json ./
 RUN npm ci --omit=dev

package.json

@@ -7,6 +7,9 @@
     "start": "node server.js",
     "test": "node --test"
   },
+  "engines": {
+    "node": ">=24"
+  },
   "dependencies": {
     "pg": "^8.22.0",
     "ws": "^8.21.1"