Add balance adjustments (M8)

- New balance_adjustments table with CRUD store, sync logging, and service methods
- SQL migrations restructured: embed fs.FS from internal/store/migrations/, apply in order via user_version
- WeekService.Balance combines closed-weeks delta + adjustments delta; BalanceSummary breakdown
- Four REST routes: GET/POST /api/balance/adjustments, PUT/DELETE /api/balance/adjustments/{id}
- Dexie schema v2 + sync apply cases for balance_adjustments
- API client: BalanceAdjustment type, balance namespace (list/create/update/delete)
- utils: composeDeltaMs / decomposeDeltaMs helpers + 8 new Vitest tests (19 total, all passing)
- History page: balance card breakdown line + full adjustments section with inline add/edit/delete

cmd/wotra/main.go

@@ -42,13 +42,14 @@ func main() {
 	entryStore := store.NewEntryStore(db)
 	closedDayStore := store.NewClosedDayStore(db)
 	closedWeekStore := store.NewClosedWeekStore(db)
+	adjustmentStore := store.NewBalanceAdjustmentStore(db)
 	settingsStore := store.NewSettingsStore(db)
 	syncStore := store.NewSyncStore(db)
 
 	entrySvc := service.NewEntryService(entryStore, closedDayStore, settingsStore, tz)
 	daySvc := service.NewDayService(entryStore, closedDayStore, closedWeekStore, settingsStore, tz)
 	settingsSvc := service.NewSettingsService(settingsStore)
-	weekSvc := service.NewWeekService(closedDayStore, closedWeekStore, entryStore, settingsStore, db, tz)
+	weekSvc := service.NewWeekService(closedDayStore, closedWeekStore, entryStore, settingsStore, adjustmentStore, syncStore, db, tz)
 
 	// Background goroutine: auto-stop entries that cross midnight
 	ctx, cancel := context.WithCancel(context.Background())