Fix search window getting stuck when hidden during the show animation

[davidmrc6]

hide() did not cancel the pending _animSeq show-animation timer scheduled by show(). When the window is hidden within the ~100 ms animation window, the orphaned timer fires after _release_ui()/_remove_events() have run, re-executing _layout() (which sets _visible = true) and re-easing the now-empty container back to opacity 255. The search box gets stuck on screen, unresponsive, with the search entry removed (placeholder gone) and no key handlers, and can only be recovered by reloading the extension (#146)

Fix: cancel _animSeq at the top of hide(), mirroring the guard in show().