feat(lint): enforce named exports only via Biome

Add noDefaultExport linting rule to prevent default export patterns
that break dual CJS/ESM compatibility.

This prevents new modules from using:
- export default value
- export default X; export { X as 'module.exports' }

Named exports work consistently across both module systems, while
default exports require .default access, breaking the API consistency.

Author: jdalton

biome.json

@@ -68,6 +68,7 @@
         "useLiteralKeys": "off"
       },
       "style": {
+        "noDefaultExport": "error",
         "noParameterAssign": "off",
         "noNonNullAssertion": "off",
         "useAsConstAssertion": "error",