fix(publish): switch to npm OIDC Trusted Publishing with id-token (#16)

Author: Copilot

.github/workflows/publish.yml

@@ -6,7 +6,8 @@ on:
       - '[0-9]*.[0-9]*.[0-9]*'
 
 permissions:
-  contents: read
+  contents: write
+  id-token: write  # npm OIDC Trusted Publishing + provenance
 
 jobs:
   publish:
@@ -33,7 +34,5 @@ jobs:
         run: cp README.md map/README.md
 
       - name: Publish map package
-        run: npm publish
+        run: npm publish --provenance --access public
         working-directory: map
-        env:
-          NODE_AUTH_TOKEN: ${{ secrets.NPM_TOKEN }}