fix(react): improve specificity for styled lazy components

[Anber]

Fixes #1415.

Summary

• Detect React.lazy targets during styled extraction.
• Preserve wrapper override specificity by duplicating the generated wrapper class when the lazy target metadata cannot be resolved.
• Add a regression test for styling a lazy component.

Why

Linaria normally emits chained selectors when styling another styled component, for example .Wrapper.Base, so wrapper styles can override base styles.

For React.lazy targets, the wrapped component metadata is hidden behind the lazy boundary and is not available synchronously during extraction. That left the wrapper rule with only one generated class, so CSS loaded later by the lazy chunk could override it.

Validation

• pnpm --filter @linaria/react test
• pnpm --filter @linaria/testkit test -- babel.test.ts -t "adds specificity when wrapping a lazy component"
• pre-commit hook: check:all, lint, sp:check

[changeset-bot]

🦋 Changeset detected

Latest commit: 9547ef9

The changes in this PR will be included in the next version bump.

This PR includes changesets to release 1 package

Name	Type
@linaria/react	Patch

Not sure what this means? Click here to learn what changesets are.

Click here if you're a maintainer who wants to add another changeset to this PR