Fix: Localize repeated background images in Cover block (#794)

[Omcodes23]

Fix: Localize repeated background images in Cover block

Summary

Localizes images used as “repeated background” in core/cover when “Localize images” is enabled. These images are copied into the theme’s assets and referenced via theme-relative URLs, removing dependency on the original uploads directory.

Fixes

• Bug: CBT does not localize images used as “repeated background” in Cover block #794

Changes

• includes/create-theme/theme-media.php
  • Enhance background-image URL parsing to support quoted and unquoted url(...).
  • Collect attrs.style.background.backgroundImage.url (Cover’s “Repeat background” attribute path).
• tests/test-theme-templates.php
  • Add test_localize_cover_repeated_background_via_attrs() to verify attribute-defined repeated backgrounds localize to /assets/images/bg.png and are replaced with a theme-relative URL.
  • Add test_localize_cover_repeated_background_inline_style() to verify inline background-image:url(...) repeated backgrounds localize to /assets/images/pattern.webp.

Rationale

Repeated background images set via the Cover block’s attributes were missed, leaving absolute upload URLs. The media extractor now covers both inline CSS and attribute-defined backgrounds to align with “Localize images”.

Risk/Compatibility

• Scoped to media extraction logic for Cover/Group backgrounds.
• Follows existing asset path conventions (/assets/images/) and parent/child theme URL handling.

Testing

• Two new unit tests cover attribute and inline style scenarios alongside existing localization tests.

Checklist

• Changes are limited to localization of Cover repeated backgrounds
• Unit tests added
• No breaking changes to existing APIs or behavior