Refine UI Style Kit 2.0.1 bridge compatibility

[Foscat]

Summary

Updates Interactive Surface CSS for ui-style-kit-css@2.0.1 compatibility and prepares the 1.2.4 patch release.

This keeps the existing class API intact while adding support for UI Style Kit 2.0.1 bridge tokens, including state-layer opacity aliases, optional surface-level tokens, and aria-current="page" selected-state styling.

Scope

• bug fix
• feature
• docs
• tests
• release/chore

Validation

npm run check:no-hex-colors
# Passed: no hex color literals found.

npm run lint:css
# Passed.

npm run test:chromium
# Passed: 35 tests.

npm test
# Passed: 105 tests across Chromium, Firefox, and WebKit.

npm run pack:dry
# Passed: verified package contents for interactive-surface-css@1.2.4.

npm run test:install was not rerun because the Playwright browsers were already installed and the full browser matrix passed.

API and Behavior Impact

• no public API changes
• class API changed
• token contract changed
• accessibility behavior changed
• motion behavior changed
• browser behavior changed

No class API changed. The token contract was expanded compatibly to consume UI Style Kit 2.0.1 bridge aliases and optional surface-level tokens.

Documentation

• README updated (if needed)
• wiki updated (if needed)
• CHANGELOG updated (if needed)

Notes

Reviewers should focus on the UI Style Kit 2.0.1 bridge behavior, especially the with-bridge import path, standalone bridge import path, data-surface-level token handling, and aria-current="page" active-state styling.