Implement AI Host functionality with model caching and job management

- Added ai_host.py to handle AI tasks with FastAPI integration.
- Introduced HostState and ModelCache classes for managing client connections and model loading.
- Implemented job submission and cancellation endpoints in the AI host.
- Enhanced tests for AI host functionality, including client tracking and job cancellation.
- Updated existing tests to accommodate changes in the operator and command structure.
- Refactored runtime commands to use request-based architecture instead of command-line arguments.
- Improved model loading logic to handle CUDA memory management and reuse models efficiently.

src/snapform/preferences.py

@@ -53,3 +53,10 @@ class SnapFormPreferences(bpy.types.AddonPreferences):
                 icon="IMPORT",
             )
             operator.job_type = "INSTALL_RUNTIME"
+        layout.separator()
+        operator = layout.operator(
+            "snapform.control_host",
+            text="Open Host Log",
+            icon="TEXT",
+        )
+        operator.action = "LOG"