fix: correct snapshot save to detect all gamme changes (drafts + validated)

handleSnapshot was only looking at active draftChanges to build the
snapshot. After validation (Valider), drafts are cleared but changes
are applied to row.codeGamme via applyDraftsToRows. This caused
handleSnapshot (Camera/Export) to save an empty snapshot that
overwrote the real one, losing all gamme changes on page reload.

Now handleSnapshot compares (draftChanges[codein] ?? row.codeGamme)
vs row.codeGammeInit to detect ALL changes, whether drafted or
already validated. Uses codeGammeInit as "before" reference (API
value, never modified).

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

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

@@ -60,13 +60,17 @@ export function FloatingSummaryBar() {
         if (rows.length === 0) return;
         setIsSavingSnapshot(true);
         try {
-            const modifiedRows = rows.filter(r => draftChanges[r.codein]);
+            // Détecter TOUS les changements : drafts actifs + changements déjà validés (codeGamme mis à jour)
+            const modifiedRows = rows.filter(r => {
+                const effectiveGamme = draftChanges[r.codein] ?? r.codeGamme;
+                return effectiveGamme !== r.codeGammeInit;
+            });
             const changes = Object.fromEntries(
                 modifiedRows.map(r => [
                     r.codein,
                     {
                         before: r.codeGammeInit,
-                        after: draftChanges[r.codein] as string
+                        after: (draftChanges[r.codein] ?? r.codeGamme) as string
                     }
                 ])
             );