CI: validate every push and pull request; stars refreshed on main and weekly

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

package.json

@@ -5,7 +5,8 @@
   "packageManager": "pnpm@11.28.3",
   "scripts": {
     "test": "node --test \"tests/*.test.mjs\"",
-    "validate": "node scripts/validate.mjs"
+    "validate": "node scripts/validate.mjs",
+    "stars": "node scripts/stars.mjs"
   },
   "dependencies": {
     "marked": "18.0.14",