## Summary
- **Auto-calculates Annual Revaluation %** (CAGR) on the frontend when
purchase price, purchase date, and current market value are all provided
— pre-fills the revaluation field while still allowing manual override
- **Generates historical monthly balance records** via linear
interpolation from purchase date to today when creating a real estate
account with complete purchase data
- New `RealEstateBalanceGeneratorService` handles balance generation
with dates on the 1st of each month (matching the existing
`ApplyRealEstateRevaluationCommand` convention)
## Changes
### Backend
- **`app/Services/RealEstateBalanceGeneratorService.php`** (new) —
Linear interpolation service that builds balance dates (purchase date,
1st of each intermediate month, today) and creates `AccountBalance`
records using `updateOrCreate`
- **`app/Http/Controllers/Settings/AccountController.php`** — Calls the
service after real estate detail creation when all three inputs are
present
### Frontend
- **`resources/js/components/accounts/account-form.tsx`** — Added CAGR
auto-calculation via `useEffect` with a `useRef` flag
(`isRevaluationManuallySet`) to avoid overwriting manual user input
### Tests
- **`tests/Feature/Services/RealEstateBalanceGeneratorServiceTest.php`**
(new) — 7 unit tests covering interpolation, edge cases (same-day
purchase, flat values, single month spans)
- **`tests/Feature/RealEstateTest.php`** — 6 new feature tests covering
historical balance generation through the controller (with/without
purchase data, same-day, flat values)
All 38 tests in `RealEstateTest.php` and all 7 service tests pass.