feat(napi/transform, oxc): add React Compiler behind a Cargo feature

[Boshen]

Summary

Exposes the React Compiler as a Cargo feature on the oxc crate and the oxc-transform napi binding, surfaced to JS as plugins.reactCompiler.

oxc crate. The react_compiler feature already existed, but nothing re-exported oxc_react_compiler — so enabling it produced a TransformOptions::react_compiler: Option<PluginOptions> field whose type callers could not name, leaving them to add their own version-matched oxc_react_compiler dependency. This adds oxc::react_compiler, which is also what lets the binding build PluginOptions through oxc rather than depending on the crate directly, as it did before #23590.

napi binding. Restores the option removed in #23590, now grouped with the other third-party plugin configs as plugins.reactCompiler. That PR rejected feature-gating because it saw two options, neither workable:

• keep the option types unconditional → a feature-off build silently ignores the option;
• gate the type surface too → build-test regenerates a .d.ts that no longer matches the checked-in one, breaking git diff --exit-code.

There's a third: gate below the type surface. The JS-facing option types are plain strings and bools with no oxc types, so they stay unconditional and only the conversion into PluginOptions is gated. A --no-default-features build then regenerates a byte-identical index.d.ts, so git diff --exit-code holds in every feature config, and a lean build passing the option gets a hard error rather than a silent no-op.

The feature is on by default so the published binary supports what the types advertise. It's a default rather than --features react_compiler in the build scripts because build already passes --features allocator, and the napi CLI forwards repeated flags as --features react_compiler allocator, which cargo misreads.

Notes

• The nesting under plugins is a JS-API grouping only. oxc::transformer::PluginsOptions has no such field — the transformer runs the compiler as its own pass before the main traversal, off TransformOptions::react_compiler — so TryFrom<TransformOptions> lifts it out of plugins before converting the rest. TransformOptions's evaluation-order doc still lists plugins.reactCompiler first for that reason.
• The compiler's options API drifted since the binding last exposed it: default_plugin_options() is gone (now PluginOptions::default()), compilationMode / panicThreshold / outputMode are enums rather than pass-through strings, and filename / isDev / enableReanimated were dropped in refactor(react_compiler): remove unused js options #24065 as unused no-ops, so those three are no longer surfaced. Unknown enum values are now rejected; target previously fell back to the React 19 runtime silently on a typo and now errors.
• This re-adds an option that shipped in 0.135.0/0.136.0 and was removed in 0.137.0, so it likely wants a changelog note.

🤖 Generated with Claude Code

[codspeed]

Merging this PR will not alter performance

✅ 67 untouched benchmarks
⏩ 9 skipped benchmarks¹

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_{Comparing react-compiler-napi (62d0731) with main (ba65790)}

Footnotes

1. 9 benchmarks were skipped, so the baseline results were used instead. If they were deleted from the codebase, click here and archive them to remove them from the performance reports. ↩