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/main.tsx

@@ -2,6 +2,7 @@ import { StrictMode } from "react";
 import { createRoot } from "react-dom/client";
 import { createRouter, RouterProvider } from "@tanstack/react-router";
 import { QueryClient, QueryClientProvider } from "@tanstack/react-query";
+import { ThemeProvider } from "./contexts/ThemeContext";
 import "./index.css";
 import { routeTree } from "./routeTree.gen";
 
@@ -19,7 +20,9 @@ const queryClient = new QueryClient({
 createRoot(document.getElementById("root")!).render(
   <StrictMode>
     <QueryClientProvider client={queryClient}>
-      <RouterProvider router={router} />
+      <ThemeProvider>
+        <RouterProvider router={router} />
+      </ThemeProvider>
     </QueryClientProvider>
   </StrictMode>,
 );