feat: multi-account financial overview dashboard (#132)

[DeekRoumy]

Summary

Closes #132

Implements a full multi-account financial overview dashboard, allowing users to manage and view all their financial accounts (bank accounts, credit cards, investments, loans, etc.) in a single unified view.

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What's Changed

Backend

New model: FinancialAccount

• Fields: name, account_type (CHECKING / SAVINGS / CREDIT_CARD / INVESTMENT / LOAN / CASH / OTHER), balance, currency, institution, last_four, color, include_in_overview, active
• Soft-delete pattern (set active=False)

New REST API /accounts:

Method	Path	Description
GET	/accounts	List active accounts
POST	/accounts	Create account
GET	/accounts/{id}	Get account
PATCH	/accounts/{id}	Update account
DELETE	/accounts/{id}	Deactivate account
GET	/accounts/overview	Aggregated multi-account overview

GET /accounts/overview returns:

• totals: net_worth, total_assets, total_liabilities
• monthly_summary: income, expenses, net_flow for selected month
• accounts: full list of accounts
• upcoming_bills: next due bills
• category_breakdown: expense breakdown by category

Schema: Added financial_accounts table to db/schema.sql with account_type enum and index.

Tests: 31 new tests in tests/test_accounts.py — all passing. Also updated conftest.py to use fakeredis for test isolation (fixes existing tests running without a Redis server).

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Frontend

New API client: app/src/api/accounts.ts — full TypeScript types + all API calls.

New page: MultiAccountDashboard at /accounts:

• Net worth summary — total assets, total liabilities, net worth cards
• Monthly summary — income, expenses, net cash flow (month picker)
• Account grid — color-coded cards per account with edit/delete actions
• Add/Edit dialog — full form (name, type, balance, currency, institution, last four, color, include in overview toggle)
• Upcoming bills list
• Category breakdown progress bar chart
• Refresh button

Navbar: Added Accounts link.
Router: Registered /accounts route in App.tsx.

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Testing

cd packages/backend
pip install fakeredis  # one-time
pytest tests/test_accounts.py -v  # 31 tests, all pass
pytest tests/                     # 53 total tests, all pass

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Acceptance Criteria

• Production-ready implementation
• Includes tests (31 new backend tests)
• Documentation updated (this PR description)

[DeekRoumy]

Hi! Just following up on this PR — it's been over 12 hours since submission. Let me know if there's any feedback or changes needed and I'll address them right away. Thanks for your time! 🙏