feat(frontend): implement TanStack Router with mobile sidebar

- Install and configure TanStack Router for type-safe routing
- Create route structure with __root.tsx layout and individual route files
- Implement mobile-responsive sidebar with collapse functionality
- Add clickable logo in sidebar that navigates to overview page
- Extract Header and Sidebar components from Dashboard for reusability
- Configure Vite with TanStack Router plugin for development
- Update main.tsx to use RouterProvider instead of direct App rendering
- Maintain existing TanStack Query integration seamlessly
- Add proper TypeScript types for all route components
- Implement responsive design with mobile overlay and hamburger menu

This replaces the tab-based navigation with URL-based routing while
maintaining the same user experience and adding powerful features like:
- Bookmarkable URLs (/transactions, /analytics, /notifications)
- Browser back/forward button support
- Direct linking capabilities
- Mobile-responsive sidebar with smooth animations
- Type-safe navigation with auto-completion

frontend/src/components/RawTransactionModal.tsx

@@ -24,7 +24,7 @@ export default function RawTransactionModal({
 
     try {
       await navigator.clipboard.writeText(
-        JSON.stringify(rawTransaction, null, 2)
+        JSON.stringify(rawTransaction, null, 2),
       );
       setCopied(true);
       setTimeout(() => setCopied(false), 2000);
@@ -78,7 +78,10 @@ export default function RawTransactionModal({
 
             <div className="mb-4">
               <p className="text-sm text-gray-600">
-                Transaction ID: <code className="bg-gray-100 px-2 py-1 rounded text-xs">{transactionId}</code>
+                Transaction ID:{" "}
+                <code className="bg-gray-100 px-2 py-1 rounded text-xs">
+                  {transactionId}
+                </code>
               </p>
             </div>
 
@@ -94,7 +97,8 @@ export default function RawTransactionModal({
                   Raw transaction data is not available for this transaction.
                 </p>
                 <p className="text-sm text-gray-500 mt-2">
-                  Try refreshing the page or check if the transaction was fetched with summary_only=false.
+                  Try refreshing the page or check if the transaction was
+                  fetched with summary_only=false.
                 </p>
               </div>
             )}