fix(critical): SQLAlchemy mapper crash + material matching for USD renders + kanban drag-to-reject

- beat_tasks.py: import app.models at module level so SQLAlchemy can
  resolve relationship("Template") and relationship("User") when domain
  models are imported in isolation inside task functions. Fixes all
  beat tasks (batch_render_notifications, recover_stuck_cad_files) that
  crashed every 60s with mapper initialization error.

- _blender_materials.py: build_mat_map_lower() now adds a slug-normalized
  key variant (re.sub([^a-z0-9]+, _, kl)) for each mat_map entry. OCC
  part names like 'F-802007_TR4-D1-H122AG' → slug 'f_802007_tr4_d1_h122ag'
  now matches USD-imported Blender objects. Existing prefix fallback
  (key.startswith(part_key)) catches AF-suffix variants.

- Orders.tsx: kanban drag-to-reject implemented. submitted/processing
  cards are draggable (cursor-grab). Rejected column highlights with
  red ring on drag-over. Drop opens reject reason modal via createPortal.
  Confirm calls rejectOrder() mutation + invalidates orders cache.

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

LEARNINGS.md

@@ -7,6 +7,27 @@
 
 ## Learnings
 
+### 2026-03-12 | Caching | Composite Cache Keys für Tessellierung
+Hash-basiertes Caching in Celery Tasks muss alle relevanten Parameter einschließen, nicht nur den Datei-Hash. Bei `generate_gltf_geometry_task` und `generate_usd_master_task` wurde der Cache-Key auf `{hash}:{linear}:{angular}:{engine}` erweitert. Außerdem: immer Disk-Existenz des gecachten Assets prüfen (`storage_key.exists()`) bevor ein Cache-Hit zurückgegeben wird — der Asset-Record kann existieren, die Datei aber nicht.
+
+### 2026-03-12 | React | Modal in <tr> braucht createPortal
+Ein Modal-Dialog, der aus einer `<tr>`-Tabellenzeile gerendert wird, erzeugt invalides HTML (`<div>` in `<tr>` nicht erlaubt). Fix: `createPortal(modal, document.body)` — rendert das Modal am Body-Root, außerhalb der Tabellen-Hierarchie.
+
+### 2026-03-12 | Prozess | ROADMAP war dem Code weit hinterher
+Pre-flight code audit vor dem Schreiben eines Plans ist zwingend erforderlich. Beim Sprint vom 2026-03-12 zeigte sich: P1 (dead-code cleanup, blender_render.py split), P5 (USD render wiring), P8 (Celery tenant context) und P10 (UI polish) waren bereits größtenteils im Code implementiert, aber nicht im ROADMAP.md reflektiert. Lesson: Immer zuerst grep/ls-Gates und Line-Count-Checks laufen lassen, bevor Tasks geplant werden.
+
+### 2026-03-12 | Material | SQLAlchemy Mapper-Fehler bei isoliertem Domain-Import
+Wenn eine Celery-Task nur `from app.domains.orders.models import Order` importiert (ohne `app.models`), kann SQLAlchemy die String-Referenzen `relationship("Template", ...)` und `relationship("User", ...)` nicht auflösen — alle Mapper-Initialisierungen schlagen fehl. Fix: `import app.models as _all_models` am Modul-Level von `beat_tasks.py` eintragen. So werden alle Models geladen bevor irgendeine Task-Funktion die Mapper initialisiert. Gilt für alle Tasks die Domain-Models direkt importieren.
+
+### 2026-03-12 | Material | OCC-Part-Namen vs. USD-Part-Keys beim Material-Matching
+OCC XCAF-Namen enthalten Bindestriche und _AF\d+-Suffixe (z.B. `GE360-HF-0011-EIN_HAELFTE_AF0_1_AF0`). Das USD-Export-Tool slugifiziert den Namen: `[^a-z0-9]+` → `_` (d.h. `ge360_hf_0011_ein_haelfte_af0_1_af0`). Blender importiert das USD-Objekt als `ge360_hf_0011_ein_haelfte` (base-name aus XCAF). Das Mat-Map aus der DB ist lowercased mit Bindestrichen. Fix: In `build_mat_map_lower()` auch eine slug-normierte Variante jeden Keys hinzufügen (`re.sub(r'[^a-z0-9]+', '_', kl).strip('_')`). Der bestehende Prefix-Fallback (`key.startswith(part_key)`) fangt dann den Rest ab.
+
+### 2026-03-12 | USD | Stale USD-Master-Assets invalidieren
+USD-Assets die vor dem `elif shape_has_loc`-Fix (Commit `de7f97b`, 2026-03-12 16:43) generiert wurden, haben fehlerhafte Geometrie (double-transform). Fix: `DELETE FROM media_assets WHERE asset_type='usd_master' AND created_at < '2026-03-12 16:43:33'` + `UPDATE cad_files SET step_file_hash = NULL WHERE id IN (...)`. Nächster Render generiert neue korrekte USD-Datei.
+
+### 2026-03-12 | USD | Mesh-Prim-Benennung für Blender 5.0
+Blender 5.0 importiert USD und kollabiert single-child Xform+Mesh-Hierarchien zu einem einzigen Objekt. Der Objektname entspricht dabei dem Leaf-Namen des Mesh-Prims (nicht dem Xform). Die Lösung: `mesh_path = f"{part_path}/{part_key}"` statt `f"{part_path}/Mesh"`. Damit importiert Blender jedes Objekt direkt mit dem korrekten part_key als Namen — kein Post-Import-Rename nötig. Blender setzt `obj["usd:path"]` nicht, daher ist der pfadbasierte Rename-Ansatz nicht funktionsfähig.
+
 ### 2026-01-15 | Architektur | Backend-Port-Konflikt
 Port 8000 war belegt → Port 8888 in `docker-compose.yml` + Vite-Proxy. Früh festlegen und in CLAUDE.md dokumentieren.
 

backend/app/tasks/beat_tasks.py

@@ -7,6 +7,11 @@ from datetime import datetime, timedelta
 
 from celery import shared_task
 
+# Eagerly import all models so SQLAlchemy can resolve string-based relationship
+# references (e.g. relationship("Template"), relationship("User")) when domain
+# models are imported individually inside task functions.
+import app.models as _all_models  # noqa: F401
+
 logger = logging.getLogger(__name__)
 
 

frontend/src/pages/Orders.tsx

@@ -1,6 +1,7 @@
 import { useQuery, useMutation, useQueryClient } from '@tanstack/react-query'
 import { Link, useNavigate } from 'react-router-dom'
-import { useState, useMemo, useEffect } from 'react'
+import { useState, useMemo, useEffect, useRef } from 'react'
+import { createPortal } from 'react-dom'
 import {
   Plus, Package, Trash2, X, Search, SlidersHorizontal,
   LayoutGrid, LayoutList, Calendar, FileSpreadsheet,
@@ -8,7 +9,7 @@ import {
   ChevronRight, Filter,
 } from 'lucide-react'
 import { toast } from 'sonner'
-import { listOrders, searchOrders, deleteOrder } from '../api/orders'
+import { listOrders, searchOrders, deleteOrder, rejectOrder } from '../api/orders'
 import { fetchThumbnailBlob } from '../api/cad'
 import type { Order, OrderDetail, OrderItem } from '../api/orders'
 import ConfirmModal from '../components/ConfirmModal'
@@ -51,6 +52,9 @@ export default function OrdersPage() {
   const [showFilters, setShowFilters] = useState(false)
   const [selected, setSelected] = useState<Set<string>>(new Set())
   const [confirmState, setConfirmState] = useState<{ open: boolean; title: string; message: string; onConfirm: () => void }>({ open: false, title: '', message: '', onConfirm: () => {} })
+  const [dragRejectOpen, setDragRejectOpen] = useState(false)
+  const [dragRejectReason, setDragRejectReason] = useState('')
+  const pendingRejectIdRef = useRef<string | null>(null)
 
   // Auto-switch to list view on narrow screens
   useEffect(() => {
@@ -167,6 +171,25 @@ export default function OrdersPage() {
     onError: (e: any) => toast.error(e.response?.data?.detail || 'Delete failed'),
   })
 
+  const rejectOrderMut = useMutation({
+    mutationFn: ({ id, reason }: { id: string; reason: string }) =>
+      rejectOrder(id, reason),
+    onSuccess: () => {
+      toast.success('Order rejected')
+      setDragRejectOpen(false)
+      setDragRejectReason('')
+      pendingRejectIdRef.current = null
+      qc.invalidateQueries({ queryKey: ['orders'] })
+    },
+    onError: (e: any) => toast.error(e.response?.data?.detail || 'Reject failed'),
+  })
+
+  const handleDropReject = (orderId: string) => {
+    pendingRejectIdRef.current = orderId
+    setDragRejectReason('')
+    setDragRejectOpen(true)
+  }
+
   const handleDeleteSelected = () => {
     const ids = [...selected]
     if (!ids.length) return
@@ -362,6 +385,7 @@ export default function OrdersPage() {
           byStatus={byStatus}
           visibleStatuses={visibleStatuses}
           onNavigate={(id) => navigate(`/orders/${id}`)}
+          onDropReject={handleDropReject}
         />
       ) : (
         <ListView
@@ -382,6 +406,52 @@ export default function OrdersPage() {
         onCancel={() => setConfirmState((s) => ({ ...s, open: false }))}
       />
 
+      {dragRejectOpen && createPortal(
+        <div
+          className="fixed inset-0 z-50 flex items-center justify-center bg-black/50"
+          onClick={(e) => { if (e.target === e.currentTarget) setDragRejectOpen(false) }}
+        >
+          <div className="bg-surface rounded-xl shadow-xl p-6 w-full max-w-sm mx-4 space-y-4">
+            <div className="flex items-center justify-between">
+              <h2 className="font-semibold text-content">Reject Order</h2>
+              <button onClick={() => setDragRejectOpen(false)} className="text-content-muted hover:text-content">
+                <X size={18} />
+              </button>
+            </div>
+            <p className="text-sm text-content-secondary">Optionally add a rejection reason:</p>
+            <textarea
+              className="w-full border border-border-default rounded-lg px-3 py-2 text-sm bg-surface-muted text-content resize-none focus:outline-none focus:ring-2 focus:ring-accent"
+              rows={3}
+              placeholder="Reason (optional)"
+              value={dragRejectReason}
+              onChange={(e) => setDragRejectReason(e.target.value)}
+              autoFocus
+            />
+            <div className="flex gap-2 justify-end">
+              <button
+                onClick={() => setDragRejectOpen(false)}
+                className="btn-secondary text-sm"
+              >
+                Cancel
+              </button>
+              <button
+                onClick={() => {
+                  if (pendingRejectIdRef.current) {
+                    rejectOrderMut.mutate({ id: pendingRejectIdRef.current, reason: dragRejectReason })
+                  }
+                }}
+                disabled={rejectOrderMut.isPending}
+                className="btn-danger text-sm"
+              >
+                {rejectOrderMut.isPending ? <Loader2 size={14} className="animate-spin" /> : <XCircle size={14} />}
+                Reject Order
+              </button>
+            </div>
+          </div>
+        </div>,
+        document.body
+      )}
+
       {/* ── Bulk delete bar ───────────────────────────────────────────────── */}
       {selected.size > 0 && (
         <div
@@ -677,19 +747,35 @@ function KanbanBoard({
   byStatus,
   visibleStatuses,
   onNavigate,
+  onDropReject,
 }: {
   byStatus: Record<Status, Order[]>
   visibleStatuses: Status[]
   onNavigate: (id: string) => void
+  onDropReject?: (orderId: string) => void
 }) {
+  const [dragOverRejected, setDragOverRejected] = useState(false)
+
   return (
     <div className="flex-1 overflow-x-auto min-h-0">
       <div className="flex gap-4 p-6 h-full min-w-max">
         {visibleStatuses.map((status) => {
           const meta = STATUS_META[status]
           const cards = byStatus[status]
+          const isRejectedCol = status === 'rejected'
           return (
-            <div key={status} className="flex flex-col w-72 min-w-[272px]">
+            <div
+              key={status}
+              className={`flex flex-col w-72 min-w-[272px] ${isRejectedCol && dragOverRejected ? 'ring-2 ring-red-400 rounded-xl' : ''}`}
+              onDragOver={isRejectedCol ? (e) => { e.preventDefault(); setDragOverRejected(true) } : undefined}
+              onDragLeave={isRejectedCol ? () => setDragOverRejected(false) : undefined}
+              onDrop={isRejectedCol ? (e) => {
+                e.preventDefault()
+                setDragOverRejected(false)
+                const orderId = e.dataTransfer.getData('orderId')
+                if (orderId && onDropReject) onDropReject(orderId)
+              } : undefined}
+            >
               <div className={`${meta.header} rounded-t-xl px-4 py-3 flex items-center gap-2`}>
                 <meta.icon size={16} className="text-white/80 shrink-0" />
                 <span className="text-white font-semibold text-sm">{meta.label}</span>
@@ -697,10 +783,10 @@ function KanbanBoard({
                   {cards.length}
                 </span>
               </div>
-              <div className="flex-1 bg-surface-muted rounded-b-xl p-2 overflow-y-auto space-y-2 min-h-[120px]">
+              <div className={`flex-1 bg-surface-muted rounded-b-xl p-2 overflow-y-auto space-y-2 min-h-[120px] ${isRejectedCol && dragOverRejected ? 'bg-red-50' : ''}`}>
                 {cards.length === 0 ? (
-                  <div className="h-20 flex items-center justify-center text-content-muted text-xs">
-                    No orders
+                  <div className={`h-20 flex items-center justify-center text-xs ${isRejectedCol && dragOverRejected ? 'text-red-400 font-medium' : 'text-content-muted'}`}>
+                    {isRejectedCol && dragOverRejected ? 'Drop to reject' : 'No orders'}
                   </div>
                 ) : (
                   cards.map((order) => (
@@ -762,12 +848,19 @@ function KanbanCard({
 
   const rp = order.render_progress
 
+  const isDraggable = order.status === 'submitted' || order.status === 'processing'
+
   return (
     <button
       onClick={onNavigate}
+      draggable={isDraggable}
+      onDragStart={isDraggable ? (e) => {
+        e.dataTransfer.setData('orderId', order.id)
+        e.dataTransfer.effectAllowed = 'move'
+      } : undefined}
       className={`w-full text-left bg-surface rounded-lg shadow-sm border border-border-default
                   border-l-4 ${meta.card} hover:shadow-md hover:-translate-y-0.5
-                  transition-all duration-150 p-3 group`}
+                  transition-all duration-150 p-3 group ${isDraggable ? 'cursor-grab active:cursor-grabbing' : ''}`}
     >
       <div className="flex items-start justify-between gap-2 mb-2">
         <span className="text-sm font-bold text-content font-mono leading-tight">

render-worker/scripts/_blender_materials.py

@@ -38,6 +38,14 @@ def build_mat_map_lower(material_map: dict) -> dict:
     for k, v in material_map.items():
         kl = k.lower().strip()
         mat_map_lower[kl] = v
+        # USD path: part_key slugs replace ALL non-alphanumeric chars with '_'
+        # (same regex as generate_part_key in export_step_to_usd.py).
+        # E.g. "F-802007_TR4-D1" → "f_802007_tr4_d1".  Add slug variant so
+        # hyphenated OCC names match USD-imported Blender objects.
+        slug_key = _re.sub(r'[^a-z0-9]+', '_', kl).strip('_')
+        if slug_key and slug_key != kl:
+            mat_map_lower.setdefault(slug_key, v)
+        # _AF\d+ stripping for GLB object names
         stripped = kl
         prev = None
         while prev != stripped: