release: v4.0.0

Bump @hyphen/sdk 3.1.0 -> 4.0.0 (major).

Breaking: minimum Node.js raised to ^22.18.0 || >=24.0.0 (drops Node 20/21),
driven by the engines.node bump (#134) and hookified@3 (#138). Also includes
a fix for QR-code creation with custom options (#137) and dependency, CI, and
publishing (OIDC trusted publishing + provenance) updates.

https://claude.ai/code/session_01Ax3tVRkBGaifDzp8xYcZhr

Author: claude

package.json

@@ -1,6 +1,6 @@
 {
   "name": "@hyphen/sdk",
-  "version": "3.1.0",
+  "version": "4.0.0",
   "description": "Hyphen SDK for Node.js",
   "repository": {
     "type": "git",