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/services/material_service.py

@@ -1,3 +1,3 @@
 # Compat shim — use app.domains.materials.service instead
-from app.domains.materials.service import resolve_material_map, seed_material_aliases_from_mappings
-__all__ = ["resolve_material_map", "seed_material_aliases_from_mappings"]
+from app.domains.materials.service import resolve_material_map, seed_material_aliases_from_mappings, find_unmapped_materials
+__all__ = ["resolve_material_map", "seed_material_aliases_from_mappings", "find_unmapped_materials"]