document NAPI-RS loader support

[biw]

Summary

Documents existing native-loader support so consumers can identify compatible packages and supported Vite versions.

What This PR Does

• Adds NAPI-RS platform-loader and companion-package support to the feature list
• Calls out ESM, CommonJS, and createRequire() compatibility
• Clarifies swift-node runtime-sidecar handling and Vite 3–8 support

What This Does Not Do

• No runtime or packaging behavior changes

Important Context

• NAPI-RS support already exists in the implementation and test suite

Code To Review Closely

README.md:11

Reviewers should verify that these advertised compatibility claims continue to match the supported loader patterns.

- **ESM and CommonJS compatible** - supports static imports, `require()`, and `createRequire()`
- **`node-gyp-build` support** - automatically detects and rewrites runtime selectors
- **`bindings` package support** - automatically handles `bindings('addon')` patterns
- **[`NAPI-RS`](https://napi.rs/) support** - automatically handles platform-specific loaders and companion packages
- **[`swift-node`](https://github.com/biw/swift-node) support** - automatically handles target-qualified addons and their runtime sidecars
- **Vite 3–8 compatible**

Gotchas, Risks, And Edge Cases

• Documentation claims need updates when loader compatibility changes

Tests And Regression Coverage

Validation Run

• pnpm test: 12 files and 205 tests passed

Coverage Assessment

Sufficient for this documentation-only change; the full suite covers the listed loader integrations and Vite compatibility.

Regressions These Tests Should Catch

• NAPI-RS platform-specific local and companion-package loaders
• node-gyp-build, bindings, swift-node, ESM, CommonJS, and Vite 7/8 behavior

Gaps And Recommended Follow-Up Tests

• No additional tests needed for documentation-only changes

Follow-Up Work

• None