Version history now available for forms

Version history has been extended to forms in Reach. Users can now view a version history panel in the form editor showing each version with its date and whether it came from AI or manual edits. The currently applied version is marked so users know what visitors see. Users can preview any past version read-only on the editor canvas before restoring it. A warning appears when restoring on a published form, explaining that changes reach new and reloaded visits immediately while already-open forms retain their loaded version. This gives users a safety net to iterate on forms without losing working versions.