feat(frontend): Complete shadcn/ui migration with dark mode support and analytics updates.

- Convert all analytics components to use shadcn Card and semantic colors
- Update RawTransactionModal with proper shadcn styling and theme support
- Fix all remaining hardcoded colors to use CSS variables (bg-card, text-foreground, etc.)
- Ensure consistent theming across light/dark modes for all components
- Add custom tooltips with semantic colors for chart components

🤖 Generated with [Claude Code](https://claude.ai/code)

Co-Authored-By: Claude <noreply@anthropic.com>

frontend/src/components/ui/label.tsx

@@ -0,0 +1,19 @@
+import * as React from "react";
+import { cn } from "@/lib/utils";
+
+const Label = React.forwardRef<
+  HTMLLabelElement,
+  React.LabelHTMLAttributes<HTMLLabelElement>
+>(({ className, ...props }, ref) => (
+  <label
+    ref={ref}
+    className={cn(
+      "text-sm font-medium leading-none peer-disabled:cursor-not-allowed peer-disabled:opacity-70",
+      className,
+    )}
+    {...props}
+  />
+));
+Label.displayName = "Label";
+
+export { Label };