Drop the always-visible sidebar: content is now full width so ~4.5
compact cards fit per row (width derived from the screen). A slide-in
menu drawer opens via the avatar (BACK/LEFT close it) and carries the
destinations + sign out with legible labels (#B0B0B0) replacing the
illegible dark-grey rail. Cards no longer scale on focus: they flip
to a white background with dark text and a white frame like
SmartTube. Grids move to 3 columns with the freed width.
