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

internal/service/week_service_test.go

@@ -22,12 +22,14 @@ func newFullServices(t *testing.T) (*service.EntryService, *service.DayService,
 	entryStore := store.NewEntryStore(db)
 	closedDayStore := store.NewClosedDayStore(db)
 	closedWeekStore := store.NewClosedWeekStore(db)
+	adjustmentStore := store.NewBalanceAdjustmentStore(db)
+	syncStore := store.NewSyncStore(db)
 	settingsStore := store.NewSettingsStore(db)
 	tz, _ := time.LoadLocation("UTC")
 
 	entrySvc := service.NewEntryService(entryStore, closedDayStore, settingsStore, tz)
 	daySvc := service.NewDayService(entryStore, closedDayStore, closedWeekStore, settingsStore, tz)
-	weekSvc := service.NewWeekService(closedDayStore, closedWeekStore, entryStore, settingsStore, db, tz)
+	weekSvc := service.NewWeekService(closedDayStore, closedWeekStore, entryStore, settingsStore, adjustmentStore, syncStore, db, tz)
 	settingsSvc := service.NewSettingsService(settingsStore)
 	return entrySvc, daySvc, weekSvc, settingsSvc
 }
@@ -246,13 +248,13 @@ func TestWeekServiceBalance(t *testing.T) {
 	ctx := context.Background()
 	_, daySvc, weekSvc, _ := newFullServices(t)
 
-	// Empty — no closed weeks yet.
+	// Empty — no closed weeks, no adjustments.
 	bal, err := weekSvc.Balance(ctx)
 	if err != nil {
 		t.Fatalf("Balance (empty): %v", err)
 	}
-	if bal.TotalDeltaMs != 0 || bal.ClosedWeekCount != 0 {
-		t.Errorf("empty: want {0,0}, got {%d,%d}", bal.TotalDeltaMs, bal.ClosedWeekCount)
+	if bal.TotalDeltaMs != 0 || bal.ClosedWeekCount != 0 || bal.AdjustmentCount != 0 {
+		t.Errorf("empty: want all zeros, got %+v", bal)
 	}
 
 	// Close two weeks as holiday (worked = expected → delta = 0 each).
@@ -279,10 +281,73 @@ func TestWeekServiceBalance(t *testing.T) {
 		t.Fatalf("Balance (populated): %v", err)
 	}
 	if bal.ClosedWeekCount != 2 {
-		t.Errorf("count: want 2, got %d", bal.ClosedWeekCount)
+		t.Errorf("closed_week_count: want 2, got %d", bal.ClosedWeekCount)
 	}
-	// Both weeks: worked == expected (holiday marks = full hours), delta = 0.
-	if bal.TotalDeltaMs != 0 {
-		t.Errorf("total_delta_ms: want 0, got %d", bal.TotalDeltaMs)
+	if bal.TotalDeltaMs != 0 || bal.WeeksDeltaMs != 0 {
+		t.Errorf("weeks-only total: want 0, got %+v", bal)
+	}
+
+	// Add a +2h adjustment.
+	now := time.Now().UnixMilli()
+	adj, err := weekSvc.CreateAdjustment(ctx, &domain.BalanceAdjustment{
+		ID: "adj-1", DeltaMs: 7_200_000, Note: "carry-over",
+		EffectiveAt: now, CreatedAt: now, UpdatedAt: now,
+	})
+	if err != nil {
+		t.Fatalf("CreateAdjustment: %v", err)
+	}
+	if adj.ID != "adj-1" {
+		t.Errorf("CreateAdjustment ID: want adj-1, got %s", adj.ID)
+	}
+
+	bal, err = weekSvc.Balance(ctx)
+	if err != nil {
+		t.Fatalf("Balance with adjustment: %v", err)
+	}
+	if bal.TotalDeltaMs != 7_200_000 {
+		t.Errorf("total with adj: want 7200000, got %d", bal.TotalDeltaMs)
+	}
+	if bal.AdjustmentsDeltaMs != 7_200_000 {
+		t.Errorf("adjustments_delta_ms: want 7200000, got %d", bal.AdjustmentsDeltaMs)
+	}
+	if bal.AdjustmentCount != 1 {
+		t.Errorf("adjustment_count: want 1, got %d", bal.AdjustmentCount)
+	}
+
+	// Zero delta rejected.
+	_, err = weekSvc.CreateAdjustment(ctx, &domain.BalanceAdjustment{
+		ID: "adj-zero", DeltaMs: 0, EffectiveAt: now, CreatedAt: now, UpdatedAt: now,
+	})
+	if err != service.ErrZeroAdjustment {
+		t.Errorf("zero delta: want ErrZeroAdjustment, got %v", err)
+	}
+
+	// Update adjustment.
+	adj.DeltaMs = 3_600_000
+	adj.UpdatedAt = now + 1
+	updated, err := weekSvc.UpdateAdjustment(ctx, adj)
+	if err != nil {
+		t.Fatalf("UpdateAdjustment: %v", err)
+	}
+	if updated.DeltaMs != 3_600_000 {
+		t.Errorf("updated delta_ms: want 3600000, got %d", updated.DeltaMs)
+	}
+	bal, _ = weekSvc.Balance(ctx)
+	if bal.TotalDeltaMs != 3_600_000 {
+		t.Errorf("balance after update: want 3600000, got %d", bal.TotalDeltaMs)
+	}
+
+	// Delete adjustment.
+	if err := weekSvc.DeleteAdjustment(ctx, "adj-1"); err != nil {
+		t.Fatalf("DeleteAdjustment: %v", err)
+	}
+	bal, _ = weekSvc.Balance(ctx)
+	if bal.TotalDeltaMs != 0 || bal.AdjustmentCount != 0 {
+		t.Errorf("balance after delete: want 0/0, got %d/%d", bal.TotalDeltaMs, bal.AdjustmentCount)
+	}
+
+	// Delete missing.
+	if err := weekSvc.DeleteAdjustment(ctx, "no-such"); err != service.ErrAdjustmentNotFound {
+		t.Errorf("delete missing: want ErrAdjustmentNotFound, got %v", err)
 	}
 }