feat(frontend): Enhance transactions page with advanced filtering and UI improvements.

- Fix amount range filters (min/max) connection to API parameters
- Add enhanced quick date filters: "This week", "This year" alongside existing options
- Create skeleton loading components (TransactionSkeleton, FiltersSkeleton) to replace simple spinner
- Add running balance column with toggle functionality for both desktop and mobile views
- Consolidate TransactionsList.tsx and TransactionsTable.tsx into single comprehensive component
- Improve UI design with better visual hierarchy, spacing, and responsive layout
- Add proper TypeScript types and fix linting issues

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

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

frontend/src/lib/api.ts

@@ -84,6 +84,8 @@ export const apiClient = {
     perPage?: number;
     search?: string;
     summaryOnly?: boolean;
+    minAmount?: number;
+    maxAmount?: number;
   }): Promise<ApiResponse<Transaction[]>> => {
     const queryParams = new URLSearchParams();
 
@@ -97,6 +99,12 @@ export const apiClient = {
     if (params?.summaryOnly !== undefined) {
       queryParams.append("summary_only", params.summaryOnly.toString());
     }
+    if (params?.minAmount !== undefined) {
+      queryParams.append("min_amount", params.minAmount.toString());
+    }
+    if (params?.maxAmount !== undefined) {
+      queryParams.append("max_amount", params.maxAmount.toString());
+    }
 
     const response = await api.get<ApiResponse<Transaction[]>>(
       `/transactions?${queryParams.toString()}`,