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

[zacharylyonstx]

Summary

Closes #132 — implements a complete multi-account financial overview dashboard allowing users to link multiple financial accounts and view a unified dashboard with aggregated data.

What Changed

Backend (packages/backend/)

• Schema: New financial_accounts table with account_type enum (CHECKING, SAVINGS, CREDIT_CARD, INVESTMENT, LOAN, OTHER), indexed on (user_id, is_active)
• Model: FinancialAccount SQLAlchemy model with full field mapping
• REST API (/accounts):
  • GET / — List accounts (filterable by include_inactive)
  • POST / — Create account with validation
  • GET /:id — Get single account
  • PATCH /:id — Partial update with field-level validation
  • DELETE /:id — Delete account
  • GET /overview — Aggregated dashboard data (by type, currency, institution) with Redis caching (5min TTL)
• All routes are JWT-protected with user-scoped data isolation
• Comprehensive input validation with descriptive error messages
• Cache invalidation on write operations

Frontend (app/)

• AccountsOverview page — Full dashboard with:
  • Net worth summary card
  • Breakdown by account type (with progress bars)
  • Breakdown by institution
  • Account cards grouped by type with inline edit/delete (hover reveal)
  • Add/Edit account modal dialog with form validation
  • Empty state with call-to-action
  • Loading and error states
• API client (api/accounts.ts) — Typed functions for all endpoints
• Routing — /accounts route added as a protected route
• Navigation — "Accounts" link added to navbar

Tests

• Backend (tests/test_accounts.py) — 8 test cases covering:
  • Full CRUD lifecycle
  • Create/update validation (missing fields, invalid types, bad balance)
  • 404 handling for non-existent accounts
  • Overview aggregation (by type, currency, institution)
  • Empty overview
  • Currency defaults from user preferences
  • All 6 account types
  • Inactive account filtering
• Frontend (__tests__/AccountsOverview.integration.test.tsx) — 4 integration tests:
  • Renders accounts with summary data
  • Empty state display
  • Add account dialog flow
  • Error state on API failure

Files Changed

File	Change
packages/backend/app/db/schema.sql	Added financial_accounts table + index
packages/backend/app/models.py	Added AccountType enum + FinancialAccount model
packages/backend/app/routes/__init__.py	Registered accounts blueprint
packages/backend/app/routes/accounts.py	New — Full CRUD + overview endpoint
packages/backend/tests/test_accounts.py	New — 8 backend test cases
app/src/api/accounts.ts	New — Typed API client
app/src/pages/AccountsOverview.tsx	New — Dashboard page component
app/src/__tests__/AccountsOverview.integration.test.tsx	New — 4 integration tests
app/src/App.tsx	Added /accounts protected route
app/src/components/layout/Navbar.tsx	Added "Accounts" nav link

[zacharylyonstx]

@rohitdash08 Multi-account financial overview dashboard is ready — full backend CRUD with aggregation, React dashboard UI, and 12 tests. 1,114 lines. Ready for review! 🙏