fix(babel): normalize resolved paths to POSIX so Windows rewrites work

[YevheniiKotyrlo]

Summary

The babel import plugin's relative-import rewriting silently no-ops on Windows. parseReactNativeSource / parseReactNativeWebSource resolve a relative source against the file being transformed and then match the result against forward-slash literals:

source = resolve(dirname(filename), source);
const internalPath = source.split("react-native/Libraries/Components/")[1];

path.resolve returns backslash-separated paths on Windows, so .split("react-native/Libraries/Components/") (and the react-native-web/dist split) never matches — internalPath is undefined, the function bails, and the import is left un-rewritten. The plugin's other cases (bare react-native / react-native-web specifiers) are plain string matches and are unaffected, so only relative imports break, and only on Windows.

This surfaces as three tests failing on Windows while green on the Linux/macOS CI:

• src/__tests__/babel/react-native.test.ts › 7. import View from '../View/View';
• src/__tests__/babel/react-native-web.test.ts › 6. import View from '../View';
• src/__tests__/babel/react-native-web.test.ts › 17. const View = _interopRequireDefault(require('../View'));

Fix

Normalize the resolved path to POSIX separators before the forward-slash matching, via a small shared helper:

export function resolvePosix(...segments: string[]): string {
  return resolve(...segments).replace(/\\/g, "/");
}

parseReactNativeSource and parseReactNativeWebSource now call resolvePosix instead of resolve. The resolve semantics are unchanged — each keeps its own base (dirname(filename) vs filename); only the separator is normalized.

import-plugin.ts's isFromThisModule is intentionally left on path.resolve: it compares two OS-native absolute paths (state.filename.startsWith(thisModuleDist)), so both sides share the platform separator and it already works — normalizing only one side would break it.

Test plan

• The three previously-failing relative-import cases now pass on Windows and remain green on POSIX.
• New src/__tests__/babel/helpers.test.ts asserts resolvePosix never returns a backslash and collapses .. like path.resolve — a platform-independent guard of the invariant (the e2e cases only exercise the Windows path on a Windows runner).
• yarn test (full suite green), yarn typecheck, yarn eslint, and prettier --check all pass.