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_ben2_onnx.py

@@ -7,7 +7,12 @@ import numpy as np
 from PIL import Image
 
 
-SOURCE_DIR = Path(__file__).resolve().parents[1] / "src" / "snapform"
+SOURCE_DIR = (
+    Path(__file__).resolve().parents[1]
+    / "src"
+    / "snapform"
+    / "ai_service"
+)
 sys.path.insert(0, str(SOURCE_DIR))
 
 import ben2_onnx