style(desktop): migrate bespoke pills to shared Badge; tidy cron/titlebar

- Sidebar toggles in the titlebar no longer carry an active highlight —
  they're plain show/hide affordances now.
- Replace every bespoke rounded-full status pill (cron, messaging,
  settings, skills) with the shared Badge (adds a `warn` tone). App radius,
  one component.
- Cron row actions use Codicons (play/debug-pause/zap/edit/trash) to match
  the rest of the chrome instead of stray lucide glyphs.

apps/desktop/src/components/ui/badge.tsx

@@ -13,6 +13,7 @@ const badgeVariants = cva(
       variant: {
         default: 'bg-primary/10 text-primary',
         muted: 'bg-muted text-muted-foreground',
+        warn: 'bg-amber-500/10 text-amber-600 dark:text-amber-300',
         destructive: 'bg-destructive/10 text-destructive',
         outline: 'border border-(--ui-stroke-secondary) text-muted-foreground'
       }