chore: pin node 24.22.1 for the eMadhra TLS vulnerability (#570)

- Dockerfile, Dockerfile.db-create and test/feature-server-test-scaffold/Dockerfile: node:24-alpine and node:18.6.0-alpine -> node:24.22.1-alpine
- CI: setup-node lts/* -> 24.x; checkout, login-action and build-push-action bumped to node24 majors
- engines.node -> >= 24.22.1 (package.json and lockfile root)

Co-authored-by: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -2,7 +2,7 @@
   "name": "jambonz-api-server",
   "version": "0.9.15",
   "engines": {
-    "node": ">= 20.0.0"
+    "node": ">= 24.22.1"
   },
   "main": "app.js",
   "scripts": {