fix(ui): vertically center close button in command palette on mobile

The X close button in the command palette dialog used the generic dialog
positioning (absolute top-4 right-4), which was visually offset from the
search input on mobile. Replace with a custom close button that matches
the input wrapper height (h-12) and uses flex centering for proper
vertical alignment.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

ui/src/components/ui/command.tsx

@@ -2,7 +2,8 @@
 
 import * as React from "react"
 import { Command as CommandPrimitive } from "cmdk"
-import { SearchIcon } from "lucide-react"
+import { SearchIcon, XIcon } from "lucide-react"
+import { Dialog as DialogPrimitive } from "radix-ui"
 
 import { cn } from "@/lib/utils"
 import {
@@ -50,11 +51,20 @@ function CommandDialog({
       </DialogHeader>
       <DialogContent
         className={cn("overflow-hidden p-0", className)}
-        showCloseButton={showCloseButton}
+        showCloseButton={false}
       >
         <Command className="[&_[cmdk-group-heading]]:text-muted-foreground **:data-[slot=command-input-wrapper]:h-12 [&_[cmdk-group-heading]]:px-2 [&_[cmdk-group-heading]]:font-medium [&_[cmdk-group]]:px-2 [&_[cmdk-group]:not([hidden])_~[cmdk-group]]:pt-0 [&_[cmdk-input-wrapper]_svg]:h-5 [&_[cmdk-input-wrapper]_svg]:w-5 [&_[cmdk-input]]:h-12 [&_[cmdk-item]]:px-2 [&_[cmdk-item]]:py-3 [&_[cmdk-item]_svg]:h-5 [&_[cmdk-item]_svg]:w-5">
           {children}
         </Command>
+        {showCloseButton && (
+          <DialogPrimitive.Close
+            data-slot="dialog-close"
+            className="ring-offset-background focus:ring-ring data-[state=open]:bg-accent data-[state=open]:text-muted-foreground absolute top-0 right-2 flex h-12 items-center rounded-xs opacity-70 transition-opacity hover:opacity-100 focus:ring-2 focus:ring-offset-2 focus:outline-hidden disabled:pointer-events-none [&_svg]:pointer-events-none [&_svg]:shrink-0 [&_svg:not([class*='size-'])]:size-4"
+          >
+            <XIcon />
+            <span className="sr-only">Close</span>
+          </DialogPrimitive.Close>
+        )}
       </DialogContent>
     </Dialog>
   )