Add a setting for passive filters

Would it be possible to add a “passive” filter mode? When enabled, the filter results would be saved locally and only refreshed manually using a reload button.

This would allow VS Code to start without waiting for all filters to load before I can begin working, especially when I know the repository content is unlikely to change.

The issue names no files, tests, or entry points. Start by locating the filter-loading flow and the extension settings registration, then trace how filter results are displayed; done means passive mode can be configured, cached results load without startup refresh, and a reload action refreshes them manually.

Written by the indexing model from the issue text.