fix(sdk): bump engines.node from >=20 to >=22.0.0 (#2465)

Node 20 reaches EOL April 30 2026. The root package already declares
>=22.0.0 and CI only runs Node 22 and 24. Align sdk/package.json so
`npm install` on Node 20 fails with a clear engines mismatch rather
than a silent install that breaks at runtime.

Co-authored-by: Claude Sonnet 4.6 <noreply@anthropic.com>

sdk/package.json

@@ -30,7 +30,7 @@
   "author": "TÂCHES",
   "license": "MIT",
   "engines": {
-    "node": ">=20"
+    "node": ">=22.0.0"
   },
   "scripts": {
     "build": "tsc",