* fix(ui): stop composer mic hover shift and stray red hover
The device-picker chevron collapsed to width 0 while idle and grew to
20px on hover, shoving the right-aligned mic button 20px left under
the cursor on every mouse-over. Detach the picker into its own
fixed-width ghost button beside the mic instead of morphing the mic's
shape into a split pill; hover only fades the picker's opacity, so the
reserved layout never shifts.
Also fixes the mic showing the send button's loud accent-red hover in
dark/openknot themes: those themes overrode .chat-send-btn:hover
directly, which outranked every variant's own hover rule (including
the intentional neutral mic hover and the stop button's danger hover).
Theme overrides now set a --chat-send-hover-background variable that
each variant's hover rule can still take precedence over.
* chore(scripts): register composer mic hover proof script
Missing package.json entry made the deadcode full-tree scan flag the
new capture script as an unused file, same as the existing
ui:proof:workboard sibling.
Peter Steinberger