feat(list): support structured two-line items

[rdlabo]

Summary

• add structured two-line layouts for inset list items containing an unslotted label and note
• left-align labels and notes while preserving vertically centered item content
• tune typography and spacing for MD3 structured list items
• keep end-slot notes compatible with the iOS-style structured list example
• account for safe-area values in inset-list note margins
• add demo coverage for MD3 and iOS-style structured lists, including wrapped labels
• document the structured list markup under the demo’s Special Coding section

Verification

• npm run fmt
• npm run lint
• npm run build
• screenshot update pending

Supersedes #18, which was reverted from main before screenshot verification.

[github-actions]

Playwright test results

 78 passed

Details

 78 tests across 1 suite
 1 minute, 35 seconds
 fa7f86b
 This detailed result covers Ionic 9 only. Ionic 8 runs against the same screenshots in a separate matrix job; check the workflow run for both results. To update the screenshots, comment with /update-screenshots.

[github-actions]

📊 Ionic 9 Playwright Test Report

View the detailed Ionic 9 report: https://rdlabo-dev.github.io/ionic-theme-md3/pr-19/

Ionic 8 runs against the same screenshots in a separate matrix job. View both results in the workflow run.

[github-actions]

📊 Ionic 9 Playwright Test Report

View the detailed Ionic 9 report: https://rdlabo-dev.github.io/ionic-theme-md3/pr-19/

Ionic 8 runs against the same screenshots in a separate matrix job. View both results in the workflow run.

[github-actions]

📊 Ionic 9 Playwright Test Report

View the detailed Ionic 9 report: https://rdlabo-dev.github.io/ionic-theme-md3/pr-19/

Ionic 8 runs against the same screenshots in a separate matrix job. View both results in the workflow run.

[github-actions]

📊 Ionic 9 Playwright Test Report

View the detailed Ionic 9 report: https://rdlabo-dev.github.io/ionic-theme-md3/pr-19/

Ionic 8 runs against the same screenshots in a separate matrix job. View both results in the workflow run.

[rdlabo]

/update-screenshots

[github-actions]

✅ Screenshots have been updated successfully!

The new screenshots have been committed to this PR.

[github-actions]

📊 Ionic 9 Playwright Test Report

View the detailed Ionic 9 report: https://rdlabo-dev.github.io/ionic-theme-md3/pr-19/

Ionic 8 runs against the same screenshots in a separate matrix job. View both results in the workflow run.