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.

docs/development.md

@@ -15,16 +15,29 @@ uv run python pack.py
 ├── src/
 │   └── snapform/
 │       ├── blender_manifest.toml
-│       ├── service.py
 │       ├── install_env.py
 │       ├── models.py
-│       ├── image_depth.py
 │       ├── operators.py
 │       ├── panel.py
 │       ├── preferences.py
 │       ├── properties.py
 │       ├── client.py
-│       └── worker.py
+│       ├── blendjob/
+│       │   ├── client.py
+│       │   ├── operator.py
+│       │   ├── service.py
+│       │   └── server.py
+│       ├── blender/
+│       │   ├── depth_plane.py
+│       │   └── surface.py
+│       └── ai_service/
+│           ├── server.py
+│           ├── model_manager.py
+│           ├── jobs.py
+│           ├── ben2_onnx.py
+│           ├── da3_onnx.py
+│           ├── moge_onnx.py
+│           └── onnx_runtime.py
 └── tests/
 ```