- Add theme-blocks.ts registry with 24 themeable blocks across 4 categories
- Extend resolver to resolve blocks, layout, effects, media, and custom CSS per scope
- Add data-theme-block attributes to all site layout blocks
- Extend ScopedThemeVars to generate CSS for block visibility, layout vars, effect vars, media vars, and custom CSS
- Rewrite admin UI with 6 tabs: Colors, Blocks, Layout, Effects, Media, Custom
- Extend server actions to save/load all new setting types
- No database migration needed - uses existing theme_scope_values table with prefixed keys
