refactor(desktop): DRY/elegance pass over PR-touched files

- Shared useDeepLinkHighlight hook collapses 3 near-identical settings
  deep-link effects (keys/mcp); config kept inline (distinct bail-clear).
- command-center: table-driven SECTION_ICONS + single errorText helper.
- clarify-tool: OPTION_ROW_CLASS + RadioDot extracted from option rows.
- desktop-controller: merge Cmd+K / Cmd+. into one keydown handler.
- statusbar-controls: hoist shared action class.
- Misc: drop redundant cn()/cursor-pointer/dead fields; tidy switch.

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

@@ -41,7 +41,7 @@ function Switch({
 }: React.ComponentProps<typeof SwitchPrimitive.Root> & VariantProps<typeof switchVariants>) {
   return (
     <SwitchPrimitive.Root className={cn(switchVariants({ size }), className)} data-slot="switch" {...props}>
-      <SwitchPrimitive.Thumb className={cn(switchThumbVariants({ size }))} data-slot="switch-thumb" />
+      <SwitchPrimitive.Thumb className={switchThumbVariants({ size })} data-slot="switch-thumb" />
     </SwitchPrimitive.Root>
   )
 }