Enhance snapshot handling by backfilling provisioned disk data and updating backfill logic

internal/tasks/inventorySnapshots_test.go

@@ -104,3 +104,19 @@ func TestBackfillSnapshotRowFromHourlyCacheNoMatch(t *testing.T) {
 		t.Fatal("expected no backfill change for missing VM")
 	}
 }
+
+func TestNeedsSnapshotBackfillIgnoresDiskOnlyGap(t *testing.T) {
+	row := InventorySnapshotRow{
+		CreationTime:   sql.NullInt64{Int64: 100, Valid: true},
+		VcpuCount:      sql.NullInt64{Int64: 2, Valid: true},
+		RamGB:          sql.NullInt64{Int64: 8, Valid: true},
+		Cluster:        sql.NullString{String: "cluster-a", Valid: true},
+		Datacenter:     sql.NullString{String: "dc-a", Valid: true},
+		SrmPlaceholder: "FALSE",
+		VmUuid:         sql.NullString{String: "uuid-1", Valid: true},
+		// ProvisionedDisk intentionally missing.
+	}
+	if needsSnapshotBackfill(row) {
+		t.Fatal("expected disk-only gap to be non-critical for sparse-row detection")
+	}
+}