refactor(libdatadog): share napi bindings without wasi

[rochdev]

Summary

Deduplicates the native N-API and WASM bindings by building both artifacts
from the shared libdatadog crate. The WASM fallback targets
wasm32-unknown-unknown, uses the napi-rs current-thread async runtime, and
does not require WASI or worker permissions.

Details

• Removes the separate libdatadog-wasm Rust crate and its duplicated bindings.
• Builds the shared binding crate for native N-API and
  wasm32-unknown-unknown.
• Transforms the raw WASM with a pinned wasm-bindgen build helper while
  preserving napi-rs exports.
• Instantiates the binding with emnapi and installs the official napi-rs
  current-thread task host for async exports.
• Brotli-compresses and embeds the WASM and complete JavaScript runtime in one
  self-contained entry point with no separate runtime assets.
• Preserves the native-first universal package with the self-contained WASM
  package as its fallback.
• Verifies that the fallback loads under Node's permission model without
  --allow-wasi or --allow-worker.
• Updates dependency validation, release CI, and size reporting for the new
  target.

Compared with the separate wasm-bindgen implementation on the base commit:

Size	Before	After	Increase
Raw WASM	317,842 B	463,436 B	145,594 B
Final inlined JavaScript	153,310 B	249,024 B	95,714 B
Brotli-compressed final JavaScript	103,668 B	187,168 B	83,500 B
Published WASM package tarball	106,137 B	188,308 B	82,171 B

The published package contains no separate runtime or worker files.

Validation

• 41 runtime, parity, exporter, transport, bundler, package, permission, and
  size-report tests on Node 24.
• WASM, exporter, and bundler coverage on Node 18; the unsupported permission
  flag test is skipped there.
• Strict TypeScript type checking.
• ESLint.
• cargo clippy --package libdatadog --target wasm32-unknown-unknown -- -D warnings.
• Artifact dependency and forbidden-code validation.

This PR was generated by Codex.

[github-actions]

Overall package size

Self size: 53.9 MB
Deduped: 53.9 MB
No deduping: 53.9 MB

Dependency sizes

| name | version | self size | total size | |------|---------|-----------|------------|

_{🤖 This report was automatically generated by heaviest-objects-in-the-universe}

[chatgpt-codex-connector]

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[Aaalibaba42]

Can't really review the "js" side of the PR

[Aaalibaba42]

This is, as per the name, unstable. The whole capability architecture was made so that we did not need to either compile to wasi nor have unstable/nightly features enabled. I'm not opposing this change of direction, but it has to be thought-out properly.

[BridgeAR]

Superseded, since napi is not being used