refactor: remove preview_method and component legacy features

Preview Method Removal:
- Remove preview method UI from Manager settings panel
- Remove /v2/manager/preview_method API endpoint (legacy)
- Remove set_preview_method() and get_current_preview_method() functions
- Remove preview_method from config read/write operations
- Clean up latent_preview imports

Use ComfyUI Settings > Execution > Live preview method instead.

Component Feature Removal:
- Delete components-manager.js entirely
- Remove ComponentBuilderDialog, load_components, set_component_policy
- Remove component policy UI from Manager settings panel
- Remove /v2/manager/policy/component API endpoint
- Remove /v2/manager/component/save and /loads API endpoints
- Remove component_policy from config read/write operations
- Remove manager_components_path from context

pyproject.toml

@@ -5,7 +5,7 @@ build-backend = "setuptools.build_meta"
 [project]
 name = "comfyui-manager"
 license = { text = "GPL-3.0-only" }
-version = "4.0.3b6"
+version = "4.0.3b7"
 requires-python = ">= 3.9"
 description = "ComfyUI-Manager provides features to install and manage custom nodes for ComfyUI, as well as various functionalities to assist with ComfyUI."
 readme = "README.md"