"Bulk add from search" button disappears when changing workspace

The button for bulk adding from search (in the search sidebar section) disappears for me if one switches between the workspaces.

Currently the code that adds the button can be found here: https://github.com/bjsi/incremental-writing/blob/91126fe1665e7dd6d1e07f6aafc1c905cb374ce6/src/main.ts#L519-L527

Specifically this line: https://github.com/bjsi/incremental-writing/blob/91126fe1665e7dd6d1e07f6aafc1c905cb374ce6/src/main.ts#L525

I'm guessing that `addSearchButton` should be called for some workspace-related event, but currently is not, but I'm ignorant on the topic, so this is just a guess.

Start in src/main.ts around lines 519-527, especially the addSearchButton call, and trace how workspace switching is handled. Identify the workspace-related event that should preserve or recreate the search sidebar button, then verify that the button remains available after switching between workspaces.

Written by the indexing model from the issue text.