feat: Complete light mode implementation with semantic theme system

- Add comprehensive light/dark mode CSS variables with semantic naming
- Implement theme-aware scrollbars using CSS variables
- Add light mode backgrounds: --bg-base, --bg-elevated, --bg-surface, etc.
- Add theme-aware borders: --border-base, --border-panel, --border-subtle
- Add semantic text colors: --foreground-secondary, --foreground-subtle
- Convert oklch colors to hex for better compatibility
- Add theme awareness to CodeMirror editors
- Update dark mode colors for consistency (background, sidebar, card, muted, input)
- Add Tailwind color mappings for semantic classes

src/components/ui/table.tsx

@@ -6,7 +6,7 @@ function Table({ className, ...props }: React.ComponentProps<"table">) {
   return (
     <div
       data-slot="table-container"
-      className="relative w-full overflow-x-auto"
+      className="relative w-full overflow-x-auto thin-scrollbar"
     >
       <table
         data-slot="table"