Add operators for model downloading and surface generation

- Implemented `DownloadModel` and `DownloadRequiredModels` operators for downloading models.
- Created `ClearModels` operator to clear model resources.
- Added `ConvertToSurface` operator for converting image empties into textured surfaces.
- Introduced `GenerateDa3Surface` and `GenerateMoge2Surface` operators for generating surfaces using DA3 and MoGe-2 models respectively.
- Developed utility functions for handling image mesh data, assigning attributes, and managing geometry nodes.
- Established runtime configuration and post-installation model downloading in `runtime.py`.

src/snapform/properties.py

@@ -6,7 +6,7 @@ import sys
 
 import bpy
 
-from .job_runtime import runtime
+from .runtime import runtime
 from . import model_catalog as shared_model_catalog