chore: bump @wyw-in-js to 1.x (major)

[Anber]

This PR updates Linaria's build-time evaluation engine (WyW) to @wyw-in-js/* ^1.0.x.

Changes:

• Bump @wyw-in-js/* across packages and examples.
• Add a Stability section to the README (https://wyw-in-js.dev/stability).
• Update testkit defaults (happyDOM: false, JSON extensions + ignore rule).
• Restore the Rollup example to build linaria-website; document the Rollup serializeTransform default + workaround.
• Add migration notes and a major Changeset (7.x).

Notes:

• WyW 1.x may promote fully-static modules to only: ['*'] and can re-evaluate modules when cached exports are incomplete; cache tests/snapshots were updated accordingly.

[changeset-bot]

🦋 Changeset detected

Latest commit: 3b53e60

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

This PR includes changesets to release 16 packages

Name	Type
@linaria/atomic	Major
@linaria/babel-plugin-interop	Major
@linaria/core	Major
@linaria/postcss-linaria	Major
@linaria/react	Major
@linaria/server	Major
@linaria/stylelint	Major
@linaria/stylelint-config-standard-linaria	Major
@linaria/testkit	Major
linaria	Major
linaria-website	Patch
vpssr-linaria-solid-example	Patch
esbuild-example	Patch
rollup-example	Patch
vite-example	Patch
webpack5-example	Patch

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