Summary

Currently, the assets loader only supports two modes for asset delivery: always
extract as separate files or always inline as base64 URIs. There is no way to
automatically inline small assets (where the base64 overhead is negligible) while
still extracting large ones — developers had to choose one strategy for all assets
or manually split rules by path.

This PR adds a maxInlineSize option (in bytes) to both assets-loader and
getAssetTransformRules. Assets whose largest scale variant is within the threshold
are inlined as base64 URIs; larger assets are extracted as separate files. The
comparison uses the largest scale variant (e.g. @3x) intentionally — when an asset
is inlined, all variants are embedded in the bundle, so the largest one determines
the worst-case size impact.

Test plan

1. Add an asset smaller than the threshold and one larger than the threshold to a
   React Native screen.
2. Configure the assets loader with maxInlineSize: .
3. Build the app — verify the small asset is inlined as a base64 URI and the large
   asset is extracted as a separate file.
4. Alternatively, use the tester app (apps/tester-app) which already has assets set
   up for manual validation.
5. Verify the option works both when passed directly to assets-loader and via
   getAssetTransformRules({ maxInlineSize: ... }).