Summary by Sourcery

Restructure integration tests by splitting controls into subfolders and update related tooling to support this layout

Enhancements:

• Resolve golden image path from the controls root directory to support nested test folders
• Convert internal image loading and comparison methods to static methods
• Add all exports in Python modules for cleaner public APIs

CI:

• Introduce a test suite matrix in the macOS integration tests GitHub Actions workflow to run each controls subfolder separately
• Disable fail-fast and update setup steps (UV and Flutter) for the CI job

Documentation:

• Expand integration_tests README with suite-specific commands for core, material, cupertino, theme, and types tests