feat: add money in and out sheets

[DavidAmunga]

Summary

• Added two new optional sheets for XLSX exports: "Money In" and "Money Out"
• These sheets provide filtered views of income and expense transactions with detailed summaries

Screenshots

## Changes Made

New Files

• app/src/services/exports/moneyInSheet.ts - Sheet displaying all incoming transactions (paidIn > 0)
• app/src/services/exports/moneyOutSheet.ts - Sheet displaying all outgoing transactions (withdrawn > 0)

Modified Files

• app/src/services/exports/index.ts - Exported new sheet functions
• app/src/types/index.ts - Added includeMoneyInSheet and includeMoneyOutSheet options to ExportOptions interface
• app/src/services/xlsxService.ts - Integrated new sheets into XLSX export workflow

Features

Money In Sheet

• Filters and displays all transactions where money was received
• Green color theme for easy visual identification
• Summary row showing total amount received and transaction count
• Sorted by most recent transactions first
• Supports both regular and paybill statement formats
• Currency formatting with visual highlights

Money Out Sheet

• Filters and displays all transactions where money was spent
• Red color theme for expense tracking
• Summary row showing total amount spent and transaction count
• Sorted by most recent transactions first
• Supports both regular and paybill statement formats
• Currency formatting with visual highlights

Both Sheets Include

• Frozen header rows for better scrolling experience
• Professional borders and styling
• Automatic number formatting for currency values
• Conditional columns for paybill statements (Transaction Type, Other Party)