## Why
### Problem
Account balance metrics computation (12-month sparklines, net worth
evolution, currency conversion) was duplicated across three controllers:
- `AccountController` — account index page metrics
- `DashboardController` — dashboard net worth evolution
- `DashboardAnalyticsController` — analytics API net worth evolution
(monthly + daily)
Each had its own `convertBalance()` method, its own BalanceLookup
iteration loop, and its own invested amount handling. Additionally,
`AccountController::show()` re-queried `categories`, `accounts`, and
`banks` — all already available as shared Inertia props from
`HandleInertiaRequests` middleware.
## What
### Changes
- **Extract `AccountMetricsService`** with three public methods:
- `getAccountMetrics()` — per-account balance metrics with sparkline
history (used by accounts index)
- `getNetWorthEvolution()` — monthly net worth evolution with
per-account balances (used by dashboard + analytics API)
- `getNetWorthDailyEvolution()` — daily net worth evolution (used by
analytics API)
- **Refactor `AccountController`** — delegate to
`AccountMetricsService`, remove 3 private methods (`getAccountMetrics`,
`formatMonth`, `convertBalance`)
- **Refactor `DashboardController`** — delegate to
`AccountMetricsService`, remove `getNetWorthEvolution` loop and
`convertBalance`
- **Refactor `DashboardAnalyticsController`** — delegate to
`AccountMetricsService` for `netWorthEvolution` and
`netWorthDailyEvolution`, remove `convertBalance`, `getBalanceAt`,
`getInvestedAmountAt` private methods
- **Remove duplicate queries from `AccountController::show()`** —
`categories`, `accounts`, `banks` are already shared by middleware
- **Add missing `encrypted` column** to the middleware's shared
`accounts` query so components that need it (EditAccountDialog, etc.)
receive it
### Impact
- **Net -87 lines** across 5 files (285 added in new service, 372
removed from controllers)
- Single source of truth for balance metrics computation
- Eliminated 3 copies of `convertBalance()` and 2 copies of the net
worth evolution loop
- Removed 3 redundant database queries from account show page
## Verification
### Tests
- All 84 related tests pass (AccountController, AccountBalance,
Dashboard, DashboardAnalytics, BalanceLookup, CashflowAnalytics) with
529 assertions
- No test changes needed — the refactoring preserves exact output shapes
b661255d09