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/domains/rendering/models.py

@@ -94,6 +94,8 @@ class ProductRenderPosition(Base):
     rotation_z: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
     is_default: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
     sort_order: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    focal_length_mm: Mapped[float | None] = mapped_column(Float, nullable=True, default=None)
+    sensor_width_mm: Mapped[float | None] = mapped_column(Float, nullable=True, default=None)
     created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
     updated_at: Mapped[datetime] = mapped_column(
         DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False
@@ -113,6 +115,8 @@ class GlobalRenderPosition(Base):
     rotation_z: Mapped[float] = mapped_column(Float, nullable=False, default=0.0)
     is_default: Mapped[bool] = mapped_column(Boolean, nullable=False, default=False)
     sort_order: Mapped[int] = mapped_column(Integer, nullable=False, default=0)
+    focal_length_mm: Mapped[float | None] = mapped_column(Float, nullable=True, default=None)
+    sensor_width_mm: Mapped[float | None] = mapped_column(Float, nullable=True, default=None)
     created_at: Mapped[datetime] = mapped_column(DateTime, default=datetime.utcnow, nullable=False)
     updated_at: Mapped[datetime] = mapped_column(
         DateTime, default=datetime.utcnow, onupdate=datetime.utcnow, nullable=False