The wifi panel now has full keyboard nav over both sections:
h/l walk the DNS provider pills
j/k walk the wifi network list (j from DNS drops into the
list; k from the top row goes back to DNS)
Enter/Space apply the highlighted DNS provider / connect to the
highlighted wifi network
Esc close the panel
Single-cursor model. The visible cursor lives at the panel root via
focusSection + dnsIndex + selectedIndex. Mouse hover doesn't draw its
own highlight — onContainsMouseChanged on each row/pill MOVES the
cursor instead. Mouse leaving doesn't clear it (the cursor stays where
attention was last; subsequent j/k pick up from there). Last action
wins, whether mouse or keyboard.
New Common.CursorSurface holds the shared chrome (fill + 1px border +
fade) and is the base for both NetworkRow and the new local
DnsProviderPill. Items pass only hasCursor + current and let the
surface render. Contract: items never read containsMouse for visuals.
That's what guarantees exactly one highlight on screen at any time.
DnsProviderPill replaces Common.PillButton for the DNS row because
PillButton's hover > active > background cascade fights the
single-cursor model — its built-in hover would draw a parallel
highlight on whatever pill the pointer is parked on, even after the
cursor moved elsewhere. PillButton stays where it fits (refresh icon,
other bar widgets) and is unchanged here.
