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

comfyui_manager/common/context.py

@@ -31,7 +31,6 @@ manager_startup_script_path:str = None
 manager_snapshot_path = None
 manager_pip_overrides_path = None
 manager_pip_blacklist_path = None
-manager_components_path = None
 manager_batch_history_path = None
 
 def update_user_directory(manager_dir):
@@ -42,7 +41,6 @@ def update_user_directory(manager_dir):
     global manager_snapshot_path
     global manager_pip_overrides_path
     global manager_pip_blacklist_path
-    global manager_components_path
     global manager_batch_history_path
 
     manager_files_path = manager_dir
@@ -61,7 +59,6 @@ def update_user_directory(manager_dir):
     manager_channel_list_path = os.path.join(manager_files_path, 'channels.list')
     manager_pip_overrides_path = os.path.join(manager_files_path, "pip_overrides.json")
     manager_pip_blacklist_path = os.path.join(manager_files_path, "pip_blacklist.list")
-    manager_components_path = os.path.join(manager_files_path, "components")
     manager_util.cache_dir = os.path.join(manager_files_path, "cache")
     manager_batch_history_path = os.path.join(manager_files_path, "batch_history")