fix: apply inset styles to all list groups

[rdlabo]

Summary

• share the supported structured-list group selector list between the iOS and MD inset styles
• apply MD fallback inset input styles to item, reorder, accordion, and radio groups
• use descendant selectors so wrapped ion-item components remain supported
• derive radio helper/error text padding from the layout's outer inset

The generated padding remains 20px for iOS and resolves to 8px for the MD fallback.

Verification

• npm run build
• Prettier check for the changed SCSS files
• git diff --check
• inspected generated iOS and MD CSS for all four group selectors and their respective 20px/8px insets
• confirmed structured-list.scss is byte-identical with ionic-theme-md3

[github-actions]

Playwright test results

 90 passed

Details

 90 tests across 2 suites
 1 minute, 53 seconds
 4187b56
 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-ios26/pr-128/

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-ios26/pr-128/

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-ios26/pr-128/

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-ios26/pr-128/

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-ios26/pr-128/

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