feat: per-order-line material override — override materials for individual renders

- Add `material_override` nullable column on OrderLine (DB migration)
- Line override takes priority over OutputType override
- PATCH /orders/{id}/lines/{id} endpoint to update material_override
- Inline dropdown on each order line in the OrderDetail page
- Amber background when override is active
- Same output type, different material per line — no need to create a new output type

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

frontend/src/api/orders.ts

@@ -55,6 +55,7 @@ export interface OrderLine {
   render_log: RenderLog | null
   render_started_at: string | null
   render_completed_at: string | null
+  material_override: string | null
   notes: string | null
   created_at: string
   updated_at: string
@@ -66,6 +67,7 @@ export interface OrderLineCreate {
   render_position_id?: string | null
   global_render_position_id?: string | null
   gewuenschte_bildnummer?: string | null
+  material_override?: string | null
   notes?: string | null
 }
 
@@ -242,6 +244,14 @@ export async function dispatchLineRender(orderId: string, lineId: string) {
   return res.data
 }
 
+export async function patchOrderLine(orderId: string, lineId: string, data: { material_override?: string | null }) {
+  const res = await api.patch<{ updated: boolean; line_id: string }>(
+    `/orders/${orderId}/lines/${lineId}`,
+    data
+  )
+  return res.data
+}
+
 export async function cancelOrderRenders(orderId: string) {
   const res = await api.post<{ cancelled: number; order_status: string; errors: string[] | null }>(
     `/orders/${orderId}/cancel-renders`

frontend/src/pages/OrderDetail.tsx

@@ -12,8 +12,8 @@ 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 } from '../api/orders'
-import { checkOrderMaterials, type UnmappedMaterial } from '../api/materials'
+import { getOrder, submitOrder, deleteOrder, unlinkCadFile, regenerateItemThumbnail, patchOrderItem, removeOrderLine, dispatchRenders, cancelLineRender, dispatchLineRender, cancelOrderRenders, splitMissingStep, generateLinesFromItems, downloadOrderRenders, rejectOrder, resubmitOrder, rejectOrderLine, patchOrderLine } 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'
 import { listOutputTypes } from '../api/outputTypes'
@@ -903,6 +903,18 @@ function OrderLineRow({
     onError: (e: any) => toast.error(e.response?.data?.detail || 'Reject failed'),
   })
 
+  const { data: allMats } = useQuery({ queryKey: ['materials'], queryFn: listMaterials })
+  const libMats = (allMats ?? []).filter((m: Material) => m.schaeffler_code !== null).sort((a: Material, b: Material) => a.name.localeCompare(b.name))
+
+  const overrideMut = useMutation({
+    mutationFn: (val: string | null) => patchOrderLine(orderId, line.id, { material_override: val }),
+    onSuccess: () => {
+      toast.success(line.material_override ? 'Material override updated' : 'Material override set')
+      qc.invalidateQueries({ queryKey: ['order', orderId] })
+    },
+    onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed to update'),
+  })
+
   const canCancel = isPrivileged && (line.render_status === 'processing' || line.render_status === 'pending') && line.output_type_id
   const canRejectLine = isPrivileged && line.item_status !== 'rejected'
 
@@ -979,6 +991,20 @@ function OrderLineRow({
               {line.render_position_name}
             </span>
           )}
+          {isPrivileged && (
+            <select
+              className="text-[10px] border border-border-default rounded px-1 py-0.5 w-full mt-1"
+              style={{ backgroundColor: line.material_override ? 'rgba(245, 158, 11, 0.1)' : 'var(--color-bg-surface)' }}
+              value={line.material_override ?? ''}
+              onChange={(e) => overrideMut.mutate(e.target.value || null)}
+              title="Material override — apply a single material to all parts for this render"
+            >
+              <option value="">No material override</option>
+              {libMats.map((m: Material) => (
+                <option key={m.id} value={m.name}>{m.name.replace('SCHAEFFLER_', '').replace(/_/g, ' ')}</option>
+              ))}
+            </select>
+          )}
         </div>
       </td>