feat: enhance inspector with JSON metadata and comment parsing

[dermatz]

This pull request refactors the MageForge inspector integration to use HTML comment markers with embedded JSON metadata for block identification, replacing the previous approach of injecting data-mageforge-* attributes directly into the DOM. The JavaScript inspector logic is updated to parse these comment markers, enabling more robust and layout-agnostic detection of block regions and their metadata. The changes improve reliability, performance, and maintainability of the inspector tooling.

Inspector Markup Refactor:

• Switched from injecting data-mageforge-* attributes on elements to wrapping block HTML with MageForge comment markers containing JSON metadata in InspectorHints.php. [1] [2]

Inspector JavaScript Updates:

• Added logic in inspector.js to parse MageForge comment markers, extract block metadata, and cache block regions for efficient lookup. [1] [2]
• Refactored block detection so inspector features (highlight, badge, panel) now use the parsed JSON metadata instead of reading attributes, and improved parent block inheritance logic for structure tab rendering. [1] [2] [3] [4]

Inspector Interaction Improvements:

• Fixed badge unpinning logic to ensure click handlers are properly managed and picker is reactivated as needed.

These changes collectively modernize the inspector's integration, making it more robust and future-proof.