feat(deps): Tailwind 3 → 4 + swap tailwindcss-animate for tw-animate-css

Ran the official @tailwindcss/upgrade tool:
- tailwind.config.ts → @theme directive in globals.css
- @tailwind base/components/utilities → @import 'tailwindcss'
- postcss.config switched from tailwindcss + autoprefixer to
  @tailwindcss/postcss (autoprefixer baked in)
- focus-visible:outline-none → focus-visible:outline-hidden (the v3
  utility was a footgun — outline still showed in forced-colors mode)

Reverted the migration tool's over-zealous variant="outline" →
variant="outline-solid" rename on CVA prop values; that rename was
meant for the Tailwind `outline:` utility, not our Button/Badge
component variants.

Swapped tailwindcss-animate (v3-style JS plugin) for tw-animate-css
(v4-native @import). Same utility surface (animate-spin, animate-in,
etc.), one fewer JS plugin in the bundle.

Fixed the upgrade tool's malformed dark variant
(@custom-variant dark (&:is(class *)) — `class` was being parsed as
a tag) to canonical &:where(.dark, .dark *).

Verified: tsc 0 errors, eslint 0 errors (16 pre-existing warnings),
vitest 1315/1315, next build clean.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

src/components/ui/command.tsx

@@ -27,7 +27,7 @@ const CommandDialog = ({ children, ...props }: DialogProps) => {
   return (
     <Dialog {...props}>
       <DialogContent className="overflow-hidden p-0">
-        <Command className="[&_[cmdk-group-heading]]:px-2 [&_[cmdk-group-heading]]:font-medium [&_[cmdk-group-heading]]:text-muted-foreground [&_[cmdk-group]:not([hidden])_~[cmdk-group]]:pt-0 [&_[cmdk-group]]:px-2 [&_[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">
+        <Command className="**:[[cmdk-group-heading]]:px-2 **:[[cmdk-group-heading]]:font-medium **:[[cmdk-group-heading]]:text-muted-foreground [&_[cmdk-group]:not([hidden])_~[cmdk-group]]:pt-0 **:[[cmdk-group]]:px-2 [&_[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>
       </DialogContent>
@@ -44,7 +44,7 @@ const CommandInput = React.forwardRef<
     <CommandPrimitive.Input
       ref={ref}
       className={cn(
-        'flex h-10 w-full rounded-md bg-transparent py-3 text-sm outline-none placeholder:text-muted-foreground disabled:cursor-not-allowed disabled:opacity-50',
+        'flex h-10 w-full rounded-md bg-transparent py-3 text-sm outline-hidden placeholder:text-muted-foreground disabled:cursor-not-allowed disabled:opacity-50',
         className,
       )}
       {...props}
@@ -92,7 +92,7 @@ const CommandGroup = React.forwardRef<
   <CommandPrimitive.Group
     ref={ref}
     className={cn(
-      'overflow-hidden p-1 text-foreground [&_[cmdk-group-heading]]:px-2 [&_[cmdk-group-heading]]:py-1.5 [&_[cmdk-group-heading]]:text-xs [&_[cmdk-group-heading]]:font-medium [&_[cmdk-group-heading]]:text-muted-foreground',
+      'overflow-hidden p-1 text-foreground **:[[cmdk-group-heading]]:px-2 **:[[cmdk-group-heading]]:py-1.5 **:[[cmdk-group-heading]]:text-xs **:[[cmdk-group-heading]]:font-medium **:[[cmdk-group-heading]]:text-muted-foreground',
       className,
     )}
     {...props}
@@ -120,7 +120,7 @@ const CommandItem = React.forwardRef<
   <CommandPrimitive.Item
     ref={ref}
     className={cn(
-      'relative flex cursor-default gap-2 select-none items-center rounded-sm px-2 py-1.5 text-sm outline-none data-[disabled=true]:pointer-events-none data-[selected=true]:bg-accent data-[selected=true]:text-accent-foreground data-[disabled=true]:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0',
+      'relative flex cursor-default gap-2 select-none items-center rounded-sm px-2 py-1.5 text-sm outline-hidden data-[disabled=true]:pointer-events-none data-[selected=true]:bg-accent data-[selected=true]:text-accent-foreground data-[disabled=true]:opacity-50 [&_svg]:pointer-events-none [&_svg]:size-4 [&_svg]:shrink-0',
       className,
     )}
     {...props}