Refactor and enhance SnapForm functionality

- Introduced MODEL_NUMBERS for better model indexing.
- Improved enum_items function to cache results and handle download status.
- Updated ActiveJob class to manage temporary input paths and added displacement_via property.
- Changed IMAGE_DEPTH_PROCESS_RES_METHOD from "lower_bound_resize" to "upper_bound_resize".
- Enhanced RunJob operator to include new properties and improved error messages.
- Modified panel layout for better user experience and added runtime installation checks.
- Updated SnapFormSettings to reflect new model properties and defaults.
- Added temporary input path management in runtime.
- Refined worker functions to improve error handling and messaging.
- Expanded tests to cover new functionality and ensure backward compatibility.
- Fixed packaging script to align with versioning conventions.

src/snapform/preferences.py

@@ -33,6 +33,7 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
     )
 
     def draw(self, _context):
+        from .operators import active_job
         from .runtime import runtime_directory, runtime_ready
 
         layout = self.layout
@@ -44,7 +45,9 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
         if runtime_ready():
             layout.label(text="Runtime is ready", icon="CHECKMARK")
         else:
-            operator = layout.operator(
+            install_row = layout.row()
+            install_row.enabled = active_job() is None
+            operator = install_row.operator(
                 "snapform.run_job",
                 text="Install Runtime",
                 icon="IMPORT",