Redesign Finance page with Dashboard, Assets, and Withdrawals tabs

- Add 3-tab structure: Dashboard, Assets, Withdrawals
- Dashboard: Net profit hero card, stats grid (revenue, investment, expenses)
- Date filters: All (default), Year, Month, Week, Custom with date range picker
- Assets: Auto-populated stock value, due amounts, custom accounts (bank, lent money, etc.)
- Withdrawals: Form to record and history to view past withdrawals
- New finance.css with modern card-based styling
- Fixed tab visibility using class='tab' pattern

Author: hiteshkrmsft