refactor(scripts): unify module extensions on .js

The root package.json already declares "type": "module", so a .js file here is
ESM and the .mjs suffix only restates what the manifest states. Renames the three
GitHub Actions scripts and follows every reference, including the six JSDoc
import("...") type annotations that would otherwise degrade to any without
throwing.

.github/workflows/update-projects.yml

@@ -38,7 +38,7 @@ jobs:
         env:
           GH_TOKEN: ${{ secrets.PAGES_FETCH_TOKEN }}
           GH_USER: tiennm99
-        run: node .github/scripts/update-projects-list.mjs
+        run: node .github/scripts/update-projects-list.js
 
       - name: Commit and push
         run: |