Add reusable local HTTP job service for Blender add-ons

- Implement JobClient for handling HTTP requests to the JobServer.
- Create ModalJobOperatorBase for managing Blender job lifecycle.
- Introduce JobContext and JobServer for job management and state handling.
- Add ServiceConnection and ServiceController for managing service processes.
- Implement job submission, cancellation, and resource management endpoints in the server.
- Ensure proper error handling and job state updates throughout the service.

tests/test_pack.py

@@ -52,13 +52,14 @@ class PackTest(unittest.TestCase):
 
                 self.assertIn("__init__.py", names)
                 self.assertIn("blender_manifest.toml", names)
-                self.assertIn("image_depth.py", names)
+                self.assertIn("blender/depth_plane.py", names)
+                self.assertIn("blender/surface.py", names)
                 self.assertIn(
                     "assets/O_SnapForm.blend",
                     names,
                 )
-                self.assertIn("worker.py", names)
-                self.assertIn("service.py", names)
+                self.assertIn("ai_service/jobs.py", names)
+                self.assertIn("ai_service/server.py", names)
                 self.assertNotIn("snapform/__init__.py", names)
                 self.assertNotIn("importer.py", names)
                 self.assertFalse(