PlayerBar: shrink-0 avatars and tighter mobile gap
Avatars and color placeholders bump from h-8 to h-9 and gain shrink-0
so they don't collapse when the action slot is busy at narrow widths.
Outer gap drops to gap-2 on mobile (md:gap-3 on desktop) so a two-button
action group doesn't push the clock against the name.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>