fix: media thumbnails, product dimensions, inline 3D viewer, GLB export

Bug A: Media Library thumbnails were gray because <img src> cannot send
JWT auth headers. Added useAuthBlob() hook (fetch + createObjectURL) in
MediaBrowser.tsx. Also fixed publish_asset Celery task to populate
product_id + cad_file_id on MediaAsset for thumbnail fallback resolution.

Bug B: Product dimensions now shown in Product Details card with Ruler
icon and "from CAD" label when cad_mesh_attributes.dimensions_mm exists.

Bug C: Replaced 128×128 CAD thumbnail with InlineCadViewer component.
Queries gltf_geometry MediaAssets, fetches GLB via auth fetch → blob URL
→ Three.js Canvas with OrbitControls. Falls back to thumbnail + "Load 3D
Model" button. Polling when GLB generation is in progress.

Bug D: trimesh was in [cad] optional extra but Dockerfile only installed
[dev]. Changed to pip install -e ".[dev,cad]" — trimesh now available in
backend container, GLB + Colors export works.

Also added bbox extraction (STL-first numpy parsing) in render_step_thumbnail
and admin "Re-extract CAD Metadata" bulk endpoint.

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

frontend/src/pages/Admin.tsx

@@ -86,6 +86,13 @@ export default function AdminPage() {
     smtp_user: string
     smtp_password: string
     smtp_from_address: string
+    gltf_scale_factor: number
+    gltf_smooth_normals: boolean
+    viewer_max_distance: number
+    viewer_min_distance: number
+    gltf_material_quality: string
+    gltf_pbr_roughness: number
+    gltf_pbr_metallic: number
   }
 
   const { data: settings } = useQuery({
@@ -106,6 +113,9 @@ export default function AdminPage() {
   const [blenderDraft, setBlenderDraft] = useState<Partial<Settings>>({})
   const blender = { ...settings, ...blenderDraft } as Settings
 
+  const [viewerDraft, setViewerDraft] = useState<Partial<Settings>>({})
+  const viewer3d = { ...settings, ...viewerDraft } as Settings
+
   const { data: rendererStatus, refetch: refetchStatus } = useQuery({
     queryKey: ['renderer-status'],
     queryFn: async () => {
@@ -157,6 +167,14 @@ export default function AdminPage() {
     onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed'),
   })
 
+  const reextractMetadataMut = useMutation({
+    mutationFn: () => api.post('/admin/settings/reextract-metadata'),
+    onSuccess: (res) => {
+      toast.success(res.data.message || 'Metadata re-extraction queued')
+    },
+    onError: (e: any) => toast.error(e.response?.data?.detail || 'Failed'),
+  })
+
   const seedWorkflowsMut = useMutation({
     mutationFn: () => api.post('/admin/settings/seed-workflows'),
     onSuccess: (res) => {
@@ -698,6 +716,18 @@ export default function AdminPage() {
                 </button>
                 <p className="text-xs text-content-muted">Generates low + high STL files for completed STEP files missing them.</p>
               </div>
+              <div className="flex flex-col gap-1">
+                <button
+                  onClick={() => reextractMetadataMut.mutate()}
+                  disabled={reextractMetadataMut.isPending}
+                  className="btn-secondary text-sm w-full justify-start"
+                  title="Re-extract OCC bounding box and sharp-edge data for all completed CAD files"
+                >
+                  <RefreshCw size={14} className={reextractMetadataMut.isPending ? 'animate-spin' : ''} />
+                  {reextractMetadataMut.isPending ? 'Queueing…' : 'Re-extract CAD Metadata'}
+                </button>
+                <p className="text-xs text-content-muted">Updates dimensions and edge data for existing files (no re-render).</p>
+              </div>
               <div className="flex flex-col gap-1">
                 <button
                   onClick={() => seedWorkflowsMut.mutate()}
@@ -961,6 +991,150 @@ export default function AdminPage() {
         />
       )}
 
+      {/* ------------------------------------------------------------------ */}
+      {/* 3D Viewer & GLB Export Settings                                     */}
+      {/* ------------------------------------------------------------------ */}
+      <div className="card">
+        <div className="p-4 border-b border-border-default">
+          <h2 className="font-semibold text-content">3D Viewer & GLB Export</h2>
+          <p className="text-sm text-content-muted mt-0.5">
+            Settings for the 3D viewer and GLB geometry export
+          </p>
+        </div>
+        <div className="p-4 space-y-4">
+          {/* Scale Factor */}
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                GLB Scale Factor (mm→m)
+              </label>
+              <input
+                type="number"
+                step="0.0001"
+                min="0.0001"
+                max="1"
+                value={viewer3d.gltf_scale_factor ?? 0.001}
+                onChange={e => setViewerDraft(d => ({ ...d, gltf_scale_factor: parseFloat(e.target.value) }))}
+                className="input w-full"
+              />
+              <p className="text-xs text-content-muted mt-0.5">Default 0.001 converts mm to meters</p>
+            </div>
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                Smooth Normals
+              </label>
+              <label className="flex items-center gap-2 mt-2 cursor-pointer">
+                <input
+                  type="checkbox"
+                  checked={viewer3d.gltf_smooth_normals ?? true}
+                  onChange={e => setViewerDraft(d => ({ ...d, gltf_smooth_normals: e.target.checked }))}
+                  className="w-4 h-4"
+                />
+                <span className="text-sm text-content">Apply Laplacian smoothing on export</span>
+              </label>
+            </div>
+          </div>
+
+          {/* Camera / Zoom Limits */}
+          <div className="grid grid-cols-2 gap-4">
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                Max Zoom-Out Distance
+              </label>
+              <input
+                type="number"
+                step="1"
+                min="1"
+                max="10000"
+                value={viewer3d.viewer_max_distance ?? 50}
+                onChange={e => setViewerDraft(d => ({ ...d, viewer_max_distance: parseFloat(e.target.value) }))}
+                className="input w-full"
+              />
+            </div>
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                Min Zoom-In Distance
+              </label>
+              <input
+                type="number"
+                step="0.001"
+                min="0.0001"
+                max="1"
+                value={viewer3d.viewer_min_distance ?? 0.001}
+                onChange={e => setViewerDraft(d => ({ ...d, viewer_min_distance: parseFloat(e.target.value) }))}
+                className="input w-full"
+              />
+            </div>
+          </div>
+
+          {/* PBR Material Quality */}
+          <div className="grid grid-cols-3 gap-4">
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                GLB Material Mode
+              </label>
+              <select
+                value={viewer3d.gltf_material_quality ?? 'pbr_colors'}
+                onChange={e => setViewerDraft(d => ({ ...d, gltf_material_quality: e.target.value }))}
+                className="input w-full"
+              >
+                <option value="none">None (geometry only)</option>
+                <option value="pbr_colors">PBR Colors (from part colors)</option>
+              </select>
+            </div>
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                PBR Roughness (0–1)
+              </label>
+              <input
+                type="number"
+                step="0.05"
+                min="0"
+                max="1"
+                value={viewer3d.gltf_pbr_roughness ?? 0.4}
+                onChange={e => setViewerDraft(d => ({ ...d, gltf_pbr_roughness: parseFloat(e.target.value) }))}
+                className="input w-full"
+              />
+            </div>
+            <div>
+              <label className="text-sm font-medium text-content-muted block mb-1">
+                PBR Metallic (0–1)
+              </label>
+              <input
+                type="number"
+                step="0.05"
+                min="0"
+                max="1"
+                value={viewer3d.gltf_pbr_metallic ?? 0.6}
+                onChange={e => setViewerDraft(d => ({ ...d, gltf_pbr_metallic: parseFloat(e.target.value) }))}
+                className="input w-full"
+              />
+            </div>
+          </div>
+
+          <div className="flex gap-2">
+            <button
+              onClick={() => {
+                updateSettingsMut.mutate(viewerDraft)
+                setViewerDraft({})
+              }}
+              disabled={Object.keys(viewerDraft).length === 0 || updateSettingsMut.isPending}
+              className="btn-primary disabled:opacity-40"
+            >
+              Save 3D Settings
+            </button>
+            {Object.keys(viewerDraft).length > 0 && (
+              <button
+                onClick={() => setViewerDraft({})}
+                className="btn-secondary"
+              >
+                Reset
+              </button>
+            )}
+          </div>
+        </div>
+      </div>
+
       {/* ------------------------------------------------------------------ */}
       {/* Material Library link                                               */}
       {/* ------------------------------------------------------------------ */}