v0.2.1 — Remove unwired Rebuild Index button

Removes the Rebuild Index button from the plugin settings panel. Grav admin forms don't support type: button, so it was rendering as an unlabeled empty text input.

The index is already rebuilt automatically:

• When the cache is missing (on first analyze)
• On every page save (via onPageSave hook)
• On every page delete (via onPageDelete hook)

So the manual button was redundant anyway.