Migrate package management from npm to pnpm.

Standardize local and CI workflows on pnpm 11.0.8, replace npm commands in docs/config, and swap lockfiles for reproducible installs.

Co-authored-by: Cursor <cursoragent@cursor.com>

package.json

@@ -12,6 +12,7 @@
   },
   "license": "MIT",
   "author": "Pandipipas",
+  "packageManager": "pnpm@11.0.8",
   "type": "module",
   "scripts": {
     "autofix": "eslint --fix",