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.

src/snapform/preferences.py

@@ -41,12 +41,11 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
         else:
             install_row = layout.row()
             install_row.enabled = active_job() is None
-            operator = install_row.operator(
-                "snapform.run_job",
+            install_row.operator(
+                "snapform.install_environment",
                 text="Install Environment",
                 icon="IMPORT",
             )
-            operator.job_type = "INSTALL_ENV"
         layout.separator()
         operator = layout.operator(
             "snapform.control_service",