feat: batch material override — apply to all lines in an order at once

- POST /orders/{id}/batch-material-override endpoint
- Dropdown above the lines table: "Apply to all lines…"
- Options: clear all overrides, or select a library material
- Updates all order lines in one request

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

frontend/src/pages/OrderDetail.tsx

@@ -12,7 +12,7 @@ import {
   XCircle, RotateCw, Info,
 } from 'lucide-react'
 import { toast } from 'sonner'
-import { getOrder, submitOrder, deleteOrder, unlinkCadFile, regenerateItemThumbnail, patchOrderItem, removeOrderLine, dispatchRenders, cancelLineRender, dispatchLineRender, cancelOrderRenders, splitMissingStep, generateLinesFromItems, downloadOrderRenders, rejectOrder, resubmitOrder, rejectOrderLine, patchOrderLine } from '../api/orders'
+import { getOrder, submitOrder, deleteOrder, unlinkCadFile, regenerateItemThumbnail, patchOrderItem, removeOrderLine, dispatchRenders, cancelLineRender, dispatchLineRender, cancelOrderRenders, splitMissingStep, generateLinesFromItems, downloadOrderRenders, rejectOrder, resubmitOrder, rejectOrderLine, patchOrderLine, batchMaterialOverride } from '../api/orders'
 import { checkOrderMaterials, listMaterials, type UnmappedMaterial, type Material } from '../api/materials'
 import UnmappedMaterialsDialog from '../components/orders/UnmappedMaterialsDialog'
 import type { OrderItem, OrderLine } from '../api/orders'
@@ -128,6 +128,18 @@ export default function OrderDetailPage() {
     }
   }
 
+  const { data: matList } = useQuery({ queryKey: ['materials'], queryFn: listMaterials })
+  const orderLibMats = (matList ?? []).filter((m: Material) => m.schaeffler_code !== null).sort((a: Material, b: Material) => a.name.localeCompare(b.name))
+
+  const batchOverrideMut = useMutation({
+    mutationFn: (val: string | null) => batchMaterialOverride(id!, val),
+    onSuccess: (data) => {
+      toast.success(`Material override ${data.material_override ? 'set' : 'cleared'} on ${data.updated} lines`)
+      qc.invalidateQueries({ queryKey: ['order', id] })
+    },
+    onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed'),
+  })
+
   const cancelAllMut = useMutation({
     mutationFn: () => cancelOrderRenders(id!),
     onSuccess: (data) => {
@@ -606,6 +618,30 @@ export default function OrderDetailPage() {
             </div>
           )}
 
+          {(order.lines?.length ?? 0) > 0 && isPrivileged && (
+            <div className="flex items-center gap-2 mb-2 px-1">
+              <span className="text-xs text-content-muted">Batch material override:</span>
+              <select
+                className="text-xs border border-border-default rounded px-2 py-1"
+                style={{ backgroundColor: 'var(--color-bg-surface)' }}
+                value=""
+                onChange={(e) => {
+                  const val = e.target.value
+                  if (val === '__clear__') batchOverrideMut.mutate(null)
+                  else if (val) batchOverrideMut.mutate(val)
+                }}
+                disabled={batchOverrideMut.isPending}
+              >
+                <option value="">Apply to all lines…</option>
+                <option value="__clear__">— Clear all overrides —</option>
+                {orderLibMats.map((m: Material) => (
+                  <option key={m.id} value={m.name}>{m.name.replace('SCHAEFFLER_', '').replace(/_/g, ' ')}</option>
+                ))}
+              </select>
+              {batchOverrideMut.isPending && <Loader2 size={12} className="animate-spin text-accent" />}
+            </div>
+          )}
+
           {(order.lines?.length ?? 0) > 0 && (
             <div className="overflow-auto">
               <table className="w-full text-sm">