- Sidebar panel no longer auto-opens on app launch when sidebar mode was
previously enabled. Panel always starts hidden; the toggle arrow on the
right edge must be clicked to open it.
- Manage tab: custom sounds now appear above built-in sounds.
- Manage tab: both sections (CUSTOM and BUILT-IN) are now collapsible
via native <details>/<summary> elements.
- Soundboard tile eye icon changed from display:none/inline to
visibility:hidden/visible so it always occupies space. Hovering no
longer shifts the tile content.
