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.

tests/test_addon.py

@@ -43,10 +43,15 @@ class AddonTest(unittest.TestCase):
                 append=lambda draw: cls.context_menu_draws.append(draw),
                 remove=lambda draw: cls.context_menu_draws.remove(draw),
             ),
+            OUTLINER_MT_object=SimpleNamespace(
+                append=lambda draw: cls.outliner_menu_draws.append(draw),
+                remove=lambda draw: cls.outliner_menu_draws.remove(draw),
+            ),
         )
         cls.registered = []
         cls.status_bar_draws = []
         cls.context_menu_draws = []
+        cls.outliner_menu_draws = []
         fake_bpy.utils = SimpleNamespace(
             register_class=cls.registered.append,
             unregister_class=cls.registered.remove,
@@ -80,6 +85,7 @@ class AddonTest(unittest.TestCase):
         self.registered.clear()
         self.status_bar_draws.clear()
         self.context_menu_draws.clear()
+        self.outliner_menu_draws.clear()
         self.addon.operators._active_job = None
         self.addon.image_depth._last_depth_plane_model = "BASE"
         self.addon.image_mesh._last_mesh_model = "BASE"
@@ -107,6 +113,10 @@ class AddonTest(unittest.TestCase):
             self.context_menu_draws,
             [self.addon.draw_image_context_menu],
         )
+        self.assertEqual(
+            self.outliner_menu_draws,
+            [self.addon.draw_image_context_menu],
+        )
 
         self.addon.unregister()
 
@@ -116,6 +126,7 @@ class AddonTest(unittest.TestCase):
         )
         self.assertEqual(self.status_bar_draws, [])
         self.assertEqual(self.context_menu_draws, [])
+        self.assertEqual(self.outliner_menu_draws, [])
 
     def test_registers_depth_plane_operator_without_cache_rebuild(self):
         self.assertIn(
@@ -149,7 +160,8 @@ class AddonTest(unittest.TestCase):
 
         menu = self.addon.SnapFormImageMenu()
         menu.layout = Layout()
-        menu.draw(None)
+        with patch.object(self.addon.runtime, "runtime_ready", return_value=True):
+            menu.draw(None)
 
         self.assertEqual(
             calls,
@@ -161,6 +173,34 @@ class AddonTest(unittest.TestCase):
             ],
         )
 
+    def test_image_context_menu_only_installs_backend_when_missing(self):
+        calls = []
+
+        class Operator:
+            job_type = None
+
+        class Layout:
+            operator_context = None
+
+            def operator(self, identifier, **options):
+                operator = Operator()
+                calls.append((identifier, options, operator))
+                return operator
+
+            def separator(self):
+                calls.append("separator")
+
+        menu = self.addon.SnapFormImageMenu()
+        menu.layout = Layout()
+        with patch.object(self.addon.runtime, "runtime_ready", return_value=False):
+            menu.draw(None)
+
+        self.assertEqual(len(calls), 1)
+        identifier, options, operator = calls[0]
+        self.assertEqual(identifier, "snapform.run_job")
+        self.assertEqual(options["text"], "Install Backend")
+        self.assertEqual(operator.job_type, "INSTALL_RUNTIME")
+
     def test_image_mesh_reference_plane_matches_image_empty_bounds(self):
         source_object = SimpleNamespace(
             data=SimpleNamespace(size=(401, 201)),
@@ -1945,13 +1985,13 @@ class AddonTest(unittest.TestCase):
     def test_host_panel_exposes_shared_host_state_and_controls(self):
         self.assertIn(self.addon.HostPanel, self.addon.CLASSES)
         self.assertIn(self.addon.ControlHost, self.addon.CLASSES)
-        self.assertEqual(self.addon.HostPanel.bl_label, "Host")
+        self.assertEqual(self.addon.HostPanel.bl_label, "AI Backend")
 
     def test_ai_operation_restarts_a_manually_stopped_host(self):
         runtime = self.addon.runtime
         connection = runtime.HostConnection(51234, "token", 42, "host")
         health = {
-            "host_schema": runtime.HOST_SCHEMA,
+            "job_protocol_version": runtime.JOB_PROTOCOL_VERSION,
             "instance_id": "host",
             "busy": False,
             "clients": 1,