chore(node): build for the runtime the image carries

`engines`, `@types/node` and the three esbuild targets said node20 while both
stages of the image have been node:24-alpine for a while — and since
24.10.2026 the development machines run 24 too. So the bundles are built for
exactly the runtime that carries them instead of for a version nobody runs
any more.

`npm run check`: 110 files, 1825 tests, green on node 24.22.1.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>

package.json

@@ -7,7 +7,7 @@
     "packages/*"
   ],
   "engines": {
-    "node": ">=20"
+    "node": ">=24"
   },
   "scripts": {
     "test": "vitest run",
@@ -20,7 +20,7 @@
   },
   "devDependencies": {
     "@playwright/test": "1.62.1",
-    "@types/node": "^20.19.0",
+    "@types/node": "^24.19.2",
     "esbuild": "^0.28.2",
     "typescript": "^5.9.0",
     "vitest": "^3.2.0"