Trackmate - Expenses

1. Bar Chart (Intact & Improved)
	•	Displays either daily (Sun–Sat) or day numbers (1–31) depending on the selected range (Week, Month, Custom).
	•	Dynamically adjusts height based on transaction values.
	•	Uses light mint green for income and deep red-orange for expenses.
	•	Always shows the last 7 days (or selected custom range), even if data is missing.

2. Transaction View Modes
	•	Toggle between Expenses, Income, and Net using a SegmentedButton.
	•	The chart updates accordingly.

3. Date Range Selector
	•	Switch between:
	•	This Week
	•	This Month
	•	Custom Range (with a showDateRangePicker)

4. Category Spend Summary
	•	Responsive grid layout with:
	•	Category title
	•	Percentage of total spend
	•	Gradient cards based on theme (light or dark)
5. Theming via theme.dart
	•	Respects both dark and light theme styling.
	•	Uses colorScheme throughout for consistent color handling.