feat: added financial summary export sheet

[DavidAmunga]

Financial Summary Export Sheet

What Changed

• Added Financial Summary Export Sheet
• Refined Multiline Detail Parsing of the Detail column in Statements

Why This Change

The charges sheet in Excel exports had suboptimal column ordering and inconsistent total display formatting, making it harder for users to quickly understand their breakdown attribution.

How to Test

1. Upload an M-PESA statement PDF
2. Select Excel export format
3. Enable "Include Financial Summary Sheet" option
4. Export and verify:
   • Columns are in logical order
   • Total charges display correctly
   • Layout is clean and readable

Type of Change

• 🐛 Bug fix (non-breaking change which fixes an issue)
• ✨ New feature (non-breaking change which adds functionality)
• 💥 Breaking change (fix or feature that would cause existing functionality to not work as expected)
• 📚 Documentation update

Screenshots

Checklist

• My code follows the project's style guidelines
• I have performed a self-review of my code
• I have tested the changes locally
• I have added a changeset for this change