feat: per-position camera settings, material alias dialog, product delete, media browser links

- Per-render-position focal_length_mm/sensor_width_mm (DB → pipeline → Blender)
- FOV-based camera distance with min clamp fix for wide-angle lenses
- Unmapped materials blocking dialog on "Dispatch Renders" with batch alias creation
- Material check endpoint (GET /orders/{id}/check-materials)
- Batch alias endpoint (POST /materials/batch-aliases)
- Quick-map "No alias" badges on Materials page
- Full product hard-delete with storage cleanup (MinIO + disk files + orphaned CadFile)
- Delete button on ProductDetail page with confirmation
- Clickable product names in Media Browser (links to product page)
- Single-line render dispatch/retry (POST /orders/{id}/lines/{id}/dispatch-render)

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

backend/app/api/routers/cad.py

@@ -313,7 +313,7 @@ async def regenerate_thumbnail(
     db: AsyncSession = Depends(get_db),
 ):
     """Queue a Celery task to reprocess the STEP file and regenerate its thumbnail."""
-    if user.role.value != "admin":
+    if user.role.value not in ("admin", "global_admin", "tenant_admin"):
         raise HTTPException(
             status_code=403,
             detail="Only admins can trigger thumbnail regeneration",