perf(grid): optimize state store with O(1) row indexing and debounced summary calculations

src/features/grid/components/floating-summary-bar.tsx

@@ -5,7 +5,7 @@ import { useSession } from "next-auth/react";
 import { BulkAiAnalyzer } from "./bulk-ai-analyzer";
 import { useSaveDrafts } from "@/features/grid/hooks/use-save-drafts";
 import { Loader2, CheckCircle, AlertCircle, RotateCcw, Camera, ChevronDown } from "lucide-react";
-import { useState, useTransition } from "react";
+import { useMemo, useState, useTransition } from "react";
 import { saveSnapshot } from "@/features/snapshots/api/save-snapshot";
 import { SuccessModal } from "@/components/shared/success-modal";
 import {
@@ -45,7 +45,7 @@ export function FloatingSummaryBar() {
         message: ""
     });
 
-    const visibleCodeins = rows.map(r => r.codein);
+    const visibleCodeins = useMemo(() => rows.map(r => r.codein), [rows]);
     const { save, hasDrafts, count } = useSaveDrafts(filters.magasin || "TOTAL", visibleCodeins);
 
     const handleSave = () => {

src/features/grid/components/grid-filter-bar.tsx

@@ -15,11 +15,13 @@ interface GridFilterBarProps {
     magasins: { code: string; nom: string }[];
 }
 
+const EMPTY_DRAFT_CHANGES: Record<string, string> = {};
+
 export function GridFilterBar({ fournisseurs, magasins }: GridFilterBarProps) {
     const filters = useGridStore((s) => s.filters);
     const setFilter = useGridStore((s) => s.setFilter);
     const rows = useGridStore((s) => s.rows);
-    const draftChanges = useGridStore((s) => s.draftChanges);
+    const draftChanges = useGridStore((s) => s.filters.codeGamme ? s.draftChanges : EMPTY_DRAFT_CHANGES);
     const router = useRouter();
     const searchParams = useSearchParams();
     const [isRefreshing, setIsRefreshing] = React.useState(false);

src/features/grid/components/heatmap-grid.tsx

@@ -86,6 +86,8 @@ interface HeatmapGridProps {
     isAdmin?: boolean;
 }
 
+const EMPTY_DRAFT_CHANGES: Record<string, GammeCode> = {};
+
 // =========================================================================
 // OPTIMISATION PERFORMANCES (React.memo + Zustand Selectors granulaires)
 // =========================================================================
@@ -272,7 +274,7 @@ export function HeatmapGrid({ onSelectionChange, isAdmin }: HeatmapGridProps) {
     const rows = useGridStore((s) => s.rows);
     const filters = useGridStore((s) => s.filters);
     const displayDensity = useGridStore((s) => s.displayDensity);
-    const draftChanges = useGridStore((s) => s.draftChanges);
+    const draftChanges = useGridStore((s) => s.filters.codeGamme ? s.draftChanges : EMPTY_DRAFT_CHANGES);
     const activeMagasin = useGridStore((s) => s.activeMagasin);
 
     // Filtre client-side par code3 (famille) et codeGamme
@@ -707,7 +709,7 @@ export function HeatmapGrid({ onSelectionChange, isAdmin }: HeatmapGridProps) {
         count: tableRows.length,
         getScrollElement: () => tableContainerRef.current,
         estimateSize: () => rowHeight,
-        overscan: 20,
+        overscan: 8,
     });
 
     const visibleColumns = table.getVisibleLeafColumns();
@@ -769,7 +771,7 @@ export function HeatmapGrid({ onSelectionChange, isAdmin }: HeatmapGridProps) {
 
             <div
                 ref={tableContainerRef}
-                className="h-full w-full overflow-auto rounded-[12px] scroll-smooth relative"
+                className="h-full w-full overflow-auto rounded-[12px] relative"
                 style={{
                     background: "var(--bg-surface)",
                     border: "1px solid var(--border)",
@@ -835,7 +837,7 @@ export function HeatmapGrid({ onSelectionChange, isAdmin }: HeatmapGridProps) {
                             const isSelected = row.getIsSelected();
 
                             return (
-                                <div key={row.id} ref={rowVirtualizer.measureElement} style={{ position: 'absolute', top: 0, left: 0, width: '100%' }}>
+                                <div key={row.id} style={{ position: 'absolute', top: 0, left: 0, width: '100%' }}>
                                     <GridRow
                                         virtualRow={virtualRow}
                                         row={row}