refactor(P11+P12): codebase hygiene — CLAUDE.md rewrite, type safety, dead code removal

- Rewrite CLAUDE.md to match current 8-service architecture (was 11, 5 deleted)
- Remove all as-any casts in OrderDetail.tsx (9 casts → 0)
- Add cad_parsed_objects/cad_part_materials to OrderItem interface
- Rename require_admin → require_global_admin across 6 router files (22 calls)
- Remove EXPORT_GLB_PRODUCTION enum + generate_gltf_production_task (dead code)
- Remove worker-thumbnail from ALLOWED_SERVICES, replace Flamenco link
- Delete obsolete PLAN.md (1455 lines) and PLAN_REFACTOR.md (1174 lines)
- Fix digit-only USD prim names with p_ prefix

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

frontend/src/pages/OrderDetail.tsx

@@ -8,7 +8,7 @@ import {
   RotateCcw, LayoutList, LayoutGrid, X,
   ChevronDown, ChevronUp, ChevronsUpDown,
   Search, SlidersHorizontal, FileSpreadsheet, Box, Film,
-  Loader2, Play, RefreshCw, ExternalLink, Ban, StopCircle, Scissors, Plus, Wand2, Download,
+  Loader2, Play, RefreshCw, Ban, StopCircle, Scissors, Plus, Wand2, Download,
   XCircle, RotateCw, Info,
 } from 'lucide-react'
 import { toast } from 'sonner'
@@ -186,7 +186,7 @@ export default function OrderDetailPage() {
   const canReject = isPrivileged && (order.status === 'submitted' || order.status === 'processing')
   const canResubmit = order.status === 'rejected' && (isPrivileged || order.created_by === user?.id)
   const rp = order.render_progress
-  const hasRetryable = rp && (rp.pending > 0 || rp.failed > 0 || (rp as any).cancelled > 0)
+  const hasRetryable = rp && (rp.pending > 0 || rp.failed > 0 || rp.cancelled > 0)
   const canDispatch = isPrivileged && (order.status === 'processing' || order.status === 'submitted' || order.status === 'completed')
   const hasActiveRenders = rp && (rp.processing > 0 || rp.pending > 0)
   const canCancelRenders = isPrivileged && order.status === 'processing' && hasActiveRenders
@@ -461,7 +461,7 @@ export default function OrderDetailPage() {
               {rp.completed}/{rp.total} completed
               {rp.processing > 0 && <span className="text-status-info-text ml-1">({rp.processing} rendering)</span>}
               {rp.failed > 0 && <span className="text-red-500 ml-1">({rp.failed} failed)</span>}
-              {(rp as any).cancelled > 0 && <span className="text-orange-500 ml-1">({(rp as any).cancelled} cancelled)</span>}
+              {rp.cancelled > 0 && <span className="text-orange-500 ml-1">({rp.cancelled} cancelled)</span>}
             </span>
             {order.status === 'processing' && rp.processing > 0 && (
               <Loader2 size={14} className="animate-spin text-amber-500 ml-auto" />
@@ -486,10 +486,10 @@ export default function OrderDetailPage() {
                 style={{ width: `${(rp.failed / rp.total) * 100}%` }}
               />
             )}
-            {(rp as any).cancelled > 0 && (
+            {rp.cancelled > 0 && (
               <div
                 className="bg-orange-300 transition-all duration-500"
-                style={{ width: `${((rp as any).cancelled / rp.total) * 100}%` }}
+                style={{ width: `${(rp.cancelled / rp.total) * 100}%` }}
               />
             )}
           </div>
@@ -939,16 +939,10 @@ function OrderLineRow({
       {/* Backend */}
       <td className="px-4 py-2">
         {line.render_backend_used ? (
-          line.render_backend_used === 'flamenco' && line.flamenco_job_id ? (
-            <a
-              href="http://localhost:8080"
-              target="_blank"
-              rel="noopener noreferrer"
-              onClick={(e) => e.stopPropagation()}
-              className="inline-flex items-center gap-1 text-xs px-2 py-0.5 rounded-full bg-status-warning-bg text-status-warning-text font-medium hover:bg-surface-hover transition-colors"
-            >
-              Flamenco <ExternalLink size={9} />
-            </a>
+          line.render_backend_used === 'flamenco' ? (
+            <span className="text-xs px-2 py-0.5 rounded-full bg-status-warning-bg text-status-warning-text font-medium">
+              Flamenco (legacy)
+            </span>
           ) : line.render_backend_used === 'celery' ? (
             <span className="text-xs px-2 py-0.5 rounded-full bg-status-info-bg text-status-info-text font-medium">
               Celery
@@ -1461,12 +1455,12 @@ function ItemTableRow({
               )}
 
               {/* CAD part material assignments */}
-              {(item as any).cad_parsed_objects && (item as any).cad_parsed_objects.length > 0 && (
+              {item.cad_parsed_objects && item.cad_parsed_objects.length > 0 && (
                 <CadPartMaterials
                   orderId={orderId}
                   itemId={item.id}
-                  partNames={(item as any).cad_parsed_objects}
-                  savedMaterials={(item as any).cad_part_materials ?? []}
+                  partNames={item.cad_parsed_objects}
+                  savedMaterials={item.cad_part_materials ?? []}
                   excelComponents={item.components}
                 />
               )}
@@ -1733,7 +1727,7 @@ function SourceSpreadsheet({
 
                   {/* Text fields */}
                   {STD_COLS.map((c) => {
-                    const raw = (item as any)[c.key]
+                    const raw = item[c.key] as string | null
                     const display = raw ?? ''
                     return (
                       <td key={c.key} className="py-0.5 px-1 border-b border-border-light">