Enhance device management and model handling in SnapForm

- Updated frame extraction logic to allow for single frame extraction.
- Integrated model readiness checks for BEN2 and DA3 models in relevant operators.
- Added directory name attribute to model specifications for better organization.
- Improved device selection logic for production and debug tasks.
- Refactored preferences to expose device settings and ensure they reflect available hardware.
- Enhanced runtime device detection and management, including support for CUDA and MPS.
- Updated tests to cover new device management features and model directory handling.
- Removed deprecated download model tests to streamline codebase.

src/snapform/properties.py

@@ -1,6 +1,7 @@
 import bpy
 
 from .models import gs_model_enum_items, model_enum_items
+from .runtime import device_enum_items
 
 
 class SnapFormSettings(bpy.types.PropertyGroup):
@@ -18,7 +19,7 @@ class SnapFormSettings(bpy.types.PropertyGroup):
         name="Extract Frames",
         description="Maximum number of consecutive frames extracted from the start of a video or frame sequence",
         default=16,
-        min=2,
+        min=1,
         soft_max=64,
     )
     model: bpy.props.EnumProperty(
@@ -32,15 +33,13 @@ class SnapFormSettings(bpy.types.PropertyGroup):
         items=gs_model_enum_items,
     )
     device: bpy.props.EnumProperty(
-        name="Device",
-        description="Inference device used by the external Runtime",
-        items=(
-            ("AUTO", "Auto", "Use CUDA, then MPS, otherwise CPU"),
-            ("CUDA", "CUDA", "Require an NVIDIA CUDA device"),
-            ("MPS", "MPS", "Use Apple Metal (MPS)"),
-            ("CPU", "CPU", "Run on CPU"),
+        name="Debug Device",
+        description=(
+            "Inference device used by Debug tasks only; production tasks use "
+            "the Device setting in the Add-on Preferences"
         ),
-        default="AUTO",
+        items=device_enum_items,
+        default=0,
     )
     process_res: bpy.props.IntProperty(
         name="Process Res",