Add a command for bulk adding search results

Currently the search results can be added to a queue by clicking the button that is added to the search sidebar section.

The code can be found here: https://github.com/bjsi/incremental-writing/blob/91126fe1665e7dd6d1e07f6aafc1c905cb374ce6/src/main.ts#L226-L241

Currently this functionality is not available, as this has not been added as a "command", like this: https://github.com/bjsi/incremental-writing/blob/91126fe1665e7dd6d1e07f6aafc1c905cb374ce6/src/main.ts#L263-L268

Is this something that would be interesting to add?

Start in src/main.ts at lines 226-241 to understand how search results are added to the queue, then compare the command registration around lines 263-268. Add a command that performs the bulk-add action and verify that it is available and adds the search results to the queue.

Written by the indexing model from the issue text.