feat(PBR): extract Blender PBR properties and apply in 3D viewer

Extract Base Color, Metallic, Roughness, Transmission, IOR from Blender
asset library materials via catalog_assets.py. Store in catalog JSON and
serve via /api/asset-libraries/pbr-map endpoint. Frontend viewers apply
PBR properties to Three.js MeshStandardMaterial using hex color strings
(avoiding Three.js ColorManagement sRGB/linear issues).

Key fixes:
- RLS bypass for material alias lookup in pbr-map endpoint
- pbrMap empty guard prevents premature grey fallback in viewers
- Cache-Control: no-cache on pbr-map requests to avoid stale data

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

frontend/src/pages/AssetLibrary.tsx

@@ -241,14 +241,17 @@ function LibraryCard({ lib }: { lib: AssetLibrary }) {
           </button>
           {expanded && (
             <div className="mt-2 flex flex-wrap gap-1">
-              {lib.catalog.materials.slice(0, MAX_VISIBLE).map((m) => (
-                <span
-                  key={m}
-                  className="text-xs px-2 py-0.5 rounded bg-surface-alt border border-border-default text-content-secondary font-mono"
-                >
-                  {m}
-                </span>
-              ))}
+              {lib.catalog.materials.slice(0, MAX_VISIBLE).map((m) => {
+                const name = typeof m === 'string' ? m : m.name
+                return (
+                  <span
+                    key={name}
+                    className="text-xs px-2 py-0.5 rounded bg-surface-alt border border-border-default text-content-secondary font-mono"
+                  >
+                    {name}
+                  </span>
+                )
+              })}
               {materialCount > MAX_VISIBLE && (
                 <span className="text-xs px-2 py-0.5 rounded bg-surface-muted text-content-muted">
                   ... and {materialCount - MAX_VISIBLE} more

frontend/src/pages/CadPreview.tsx

@@ -27,14 +27,6 @@ export default function CadPreviewPage() {
     refetchInterval: generating ? 3_000 : false,
   })
 
-  // Load production GLB if available
-  const { data: productionAssets } = useQuery({
-    queryKey: ['media-assets', id, 'gltf_production'],
-    queryFn: () => getMediaAssets({ cad_file_id: id!, asset_types: ['gltf_production'] }),
-    enabled: !!id,
-    staleTime: 30_000,
-  })
-
   // Load blend assets for download
   const { data: blendAssets } = useQuery({
     queryKey: ['media-assets', id, 'blend_production'],
@@ -66,7 +58,6 @@ export default function CadPreviewPage() {
   }
 
   const latestGltf = gltfAssets?.[0]
-  const latestProduction = productionAssets?.[0]
   const latestBlend = blendAssets?.[0]
 
   // While checking for assets, show a neutral loading screen (don't attempt to render ThreeDViewer)
@@ -80,7 +71,7 @@ export default function CadPreviewPage() {
   }
 
   // No GLB at all — show generate prompt
-  if (!latestGltf && !latestProduction) {
+  if (!latestGltf) {
     return (
       <div className="fixed inset-0 z-50 flex flex-col bg-gray-950">
         <div className="flex items-center justify-between px-5 py-3 bg-gray-900 border-b border-gray-800">
@@ -129,14 +120,11 @@ export default function CadPreviewPage() {
       cadFileId={id}
       onClose={() => navigate(-1)}
       geometryGltfUrl={latestGltf?.download_url ?? undefined}
-      productionGltfUrl={latestProduction?.download_url ?? undefined}
       hasGeometryGlb={!!latestGltf}
-      hasProductionGlb={!!latestProduction}
       isGeneratingGeometry={generating}
       onGenerateGeometry={() => generateMutation.mutate()}
       downloadUrls={{
         glb: latestGltf?.download_url ?? undefined,
-        production: latestProduction?.download_url ?? undefined,
         blend: latestBlend?.download_url ?? undefined,
       }}
     />

frontend/src/pages/ProductDetail.tsx

@@ -22,7 +22,7 @@ import { useAuthStore, isAdmin as checkIsAdmin, isPrivileged as checkIsPrivilege
 import { generateGltfGeometry, resetStuckProcessing } from '../api/cad'
 import { listMediaAssets as getMediaAssets } from '../api/media'
 import InlineCadViewer from '../components/cad/InlineCadViewer'
-import { convertCadPartMaterials } from '../components/cad/cadUtils'
+import { convertCadPartMaterials, normalizeMeshName } from '../components/cad/cadUtils'
 import RenderInfoModal from '../components/renders/RenderInfoModal'
 
 function GlbDownloadButton({
@@ -163,12 +163,24 @@ export default function ProductDetailPage() {
     if (!product || materialsDirty) return
     const parsedNames = product.cad_parsed_objects ?? []
     if (parsedNames.length > 0) {
-      // Build rows from parsed STEP objects, pre-filling any saved material assignments
-      const savedMap = new Map(
-        (product.cad_part_materials || []).map((m) => [m.part_name, m.material])
-      )
+      // Deduplicate by normalized name — instances like _AF0, _AF1 share the same material
+      const seen = new Set<string>()
+      const uniqueNames: string[] = []
+      for (const name of parsedNames) {
+        const normalized = normalizeMeshName(name)
+        if (!seen.has(normalized)) {
+          seen.add(normalized)
+          uniqueNames.push(normalized)
+        }
+      }
+      // Pre-fill from saved assignments (try both exact and normalized keys)
+      const savedMap = new Map<string, string>()
+      for (const m of (product.cad_part_materials || [])) {
+        const key = normalizeMeshName(m.part_name)
+        if (!savedMap.has(key) && m.material) savedMap.set(key, m.material)
+      }
       setMaterialRows(
-        parsedNames.map((name) => ({ part_name: name, material: savedMap.get(name) ?? '' }))
+        uniqueNames.map((name) => ({ part_name: name, material: savedMap.get(name) ?? '' }))
       )
     } else {
       // Fallback: show whatever is saved (no parsed objects yet)