Route all search modal open/close through the JS hook via custom DOM
events so the _closing flag is always correctly managed. Prevents the
modal flashing back after Escape when a search response is in flight.
Add If-None-Match / 304 Not Modified handling to the image controller
so browsers don't re-download images on revalidation.
Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>