Add requireConfig setting to disable extension unless Oxlint config is present #11628
Description
The Oxlint VSCode extension currently runs unconditionally, even in projects that do not use Oxlint. This creates unnecessary overhead and false positives in workspaces where Oxlint is not configured or intended to be used.
Introduce a requireConfig setting in the extension's configuration, similar to Prettier and Biome. When set to true, the extension should only activate if an Oxlint config file is present in the workspace root.