Refactor AI Host to Backend Service and update related components

- Renamed references from "AI Host" to "Backend Service" throughout the codebase for consistency.
- Updated the registration and unregistration of context menus to include the Outliner.
- Changed the job protocol versioning and related constants for clarity.
- Modified the runtime installation messages and error handling to reflect the new terminology.
- Adjusted the user interface labels and messages in panels and operators to align with the new Backend Service terminology.
- Updated tests to ensure they reflect the changes in naming and functionality.
- Changed default value for background depth in geometry nodes asset to -1.0 for better handling of depth planes.

src/snapform/preferences.py

@@ -11,7 +11,7 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
     storage_root: bpy.props.StringProperty(
         name="Storage Root",
         description=(
-            "Shared user-writable storage for Runtime, models and jobs; "
+            "Shared user-writable storage for Backend Environment, models and jobs; "
             "all Blender versions can use the same directory"
         ),
         subtype="DIR_PATH",
@@ -35,22 +35,22 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
         layout.prop(self, "storage_root")
         layout.prop(self, "device")
         layout.separator()
-        layout.label(text=f"Runtime: {runtime_directory()}")
+        layout.label(text=f"Backend Environment: {runtime_directory()}")
         if runtime_ready():
-            layout.label(text="Runtime is ready", icon="CHECKMARK")
+            layout.label(text="Backend Environment is ready", icon="CHECKMARK")
         else:
             install_row = layout.row()
             install_row.enabled = active_job() is None
             operator = install_row.operator(
                 "snapform.run_job",
-                text="Install Runtime",
+                text="Install Backend",
                 icon="IMPORT",
             )
             operator.job_type = "INSTALL_RUNTIME"
         layout.separator()
         operator = layout.operator(
             "snapform.control_host",
-            text="Open Host Log",
+            text="Open Service Log",
             icon="TEXT",
         )
         operator.action = "LOG"