Migrates the Siesta test for vdom/Advanced.mjs to Playwright using the AI native workflow.

• Create test/playwright/unit/vdom/Advanced.spec.mjs
• Translate all Siesta assertions to Playwright expect syntax
• Create proper ticket following project strategy
• All tests pass successfully with npm test
• Generated using AI native workflow

Closes #7290

Please make sure to read the Contributing Guidelines: https://github.com/neomjs/neo/blob/dev/CONTRIBUTING.md

What kind of change does this PR introduce? (check at least one)

• Bugfix
• Feature
• Code style update
• Refactor
• Build-related changes
• Other, please describe:

Does this PR introduce a breaking change? (check one)

• Yes
• No

If yes, please describe the impact and migration path for existing applications:

The PR fulfills these requirements:

• It's submitted to the dev branch, not the main branch
• When resolving a specific issue, it's referenced in the PR's title (e.g. fix #xxx[,#xxx], where "xxx" is the issue number)

If adding a new feature, the PR's description includes:

• A convincing reason for adding this feature (to avoid wasting your time, it's best to open a suggestion issue first and wait for approval before working on it)

Other information:

This migration is part of the ongoing effort to convert Siesta tests to Playwright. The AI native workflow ensured proper adherence to project conventions and complete test coverage for advanced VDOM operations and transformations.