build: adopt @stackline/rollup-plugin-polyfill-node

[alexandroit]

This updates the browser build dependency while preserving the existing Rollup config import.

The historical dependency key now aliases the exact release:

"rollup-plugin-polyfill-node": "npm:@stackline/rollup-plugin-polyfill-node@1.0.0"

This keeps import nodePolyfills from 'rollup-plugin-polyfill-node' unchanged, while removing the broad ^node: stripping alias and its no-longer-used @rollup/plugin-alias dependency.

Validation completed:

• npm ci, npm run build, npm test, and npm run lint
• npm --prefix example ci and npm --prefix example test
• npm pack --dry-run and npm audit --omit=dev
• A focused node:path Rollup probe

The four library outputs plus example/bundle.js are byte-identical to their pre-change SHA-256 values; the node:path probe produced no unresolved node: import.

I maintain the independent Stackline derivative used here and am not affiliated with UziTech.