Finance: remove Other Charges, add expense pie chart and Sankey diagram

[Copilot]

Removes the Other Charges option from the Finance page and replaces it with a Charts tab containing an SVG pie chart and Sankey diagram for visualizing spending.

Removed

• Other Charges button, tab, list, and all related logic (renderCharges, charge branches in saveFinance/deleteFinance/openFinanceModal, charge contribution to updateFinanceSummary)

Added

• Charts tab replacing the Other Charges tab, with two visualizations implemented in pure SVG (no external dependencies):
  • Expense pie chart — breaks down expenses by category with a color-coded legend and percentage labels
  • Sankey diagram — shows proportional flow from income sources to expense categories

Summary card update

updateFinanceSummary now computes totals from expenses and revenue only; charges no longer factor into the net balance.

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Original prompt

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This section details on the original issue you should resolve

<issue_title>Remove "Other Charges"</issue_title>
<issue_description>Remove the other charges option from the Finance page. Users would also like to be able to visualize their spending (expenses) with a pie chart and Sankey diagram.</issue_description>

Comments on the Issue (you are @copilot in this section)

• Fixes Remove "Other Charges" #58

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[JoeProgrammer88]

The other charges related tests need to be removed

[JoeProgrammer88]

@copilot try again

[JoeProgrammer88]

@copilot try again

[Copilot]

@copilot try again

Done in commit 61aba2c. Removed the charge management describe block (3 tests) from tests/storage.test.ts and updated the e2e tab-switching test in e2e/app.spec.ts to use the charts tab instead of charges. All 84 remaining tests pass.