Create Year-Over-Year Comparison Analysis

[pyang4s]

Description:
Add a notebook section to compare financial metrics across different years.

Acceptance Criteria:

• Create queries to aggregate data by year
• Calculate YoY growth rates for income and expenses
• Create line charts showing trends over time
• Add breakdown by category with YoY comparison
• Include savings rate trend analysis
• Add visualization with Plotly
• Document in notebooks/README.md

Estimated Effort: 2-3 hours