feat: rework menu navigation and custom content flows

[TheSilentPro]

• Rework main, browse, tags, collections, hidden heads, settings, and edit menu layouts
• Add create/edit/delete flows for custom categories, tags, and collections
• Add custom heads admin menu and draft-only admin visibility
• Add persistent draft handling for custom heads and categories
• Add GUI selectors for category, tag, and collection selection during head creation
• Add tag and collection filtering/search controls
• Add refresh/reload confirmation menus
• Add economy price editing for heads and categories
• Improve permission-scoped visibility for categories, custom content, and settings
• Improve head/category display formatting in user/admin messages
• Update GUI and message configuration defaults