fix(gallery): define only the destructive token that is actually read

The previous commit deleted --color-success for being dead and then added
--destructive-foreground, which is equally dead. Nothing under gallery/ reads
it in any form: the destructive button variant is deliberately transparent at
rest and colours its TEXT, so it uses text-muted-foreground with a
hover:text-destructive, and Tailwind drops --color-destructive-foreground from
the compiled output entirely. Removed, so only --destructive is defined, which
15 call sites do read.

The --color-success deletion is reverted too. It is pre-existing, inert, and
six other mapped-but-unused tokens sit beside it, so removing that one and
leaving the rest was arbitrary rather than principled, and it put an unrelated
pre-existing cleanup inside a branding PR. The net change to input.css is now
one corrected comment.

Author: vivek7405

gallery/app/layout.ts

@@ -109,15 +109,17 @@ export default function RootLayout({ children }: { children: unknown }) {
           --border-strong:      light-dark(oklch(0.78 0.014 70 / 0.95), oklch(0.36 0.02 60 / 0.95));
           --input:              light-dark(oklch(0.88 0.012 70 / 0.9), oklch(0.24 0.015 60 / 0.9));
           --ring:               light-dark(oklch(0.63 0.17 50), oklch(0.78 0.18 58));
-          /* public/input.css maps --color-destructive, and 20 call sites across
-             the demos use text-destructive / bg-destructive for validation
-             errors, but nothing ever DEFINED it. An undefined var() left every
-             error message painting in the ordinary foreground colour and the
-             destructive button variant with no fill at all. Values follow the
-             @webjsdev/ui registry theme, warmed a few degrees of hue to sit in
-             this palette rather than beside it. */
+          /* public/input.css maps --color-destructive, and the demos use
+             text-destructive for validation errors and hover:bg-destructive/10
+             on the destructive button, but nothing ever DEFINED it. An
+             undefined var() left every error message painting in the ordinary
+             foreground colour and the button's hover fill absent. Value follows
+             the @webjsdev/ui registry theme, warmed a few degrees of hue to sit
+             in this palette rather than beside it. Only this one token: the
+             matching -foreground is mapped but read by nothing here, since the
+             destructive variant is deliberately transparent at rest and colours
+             its TEXT, so defining it would be dead weight. */
           --destructive:            light-dark(oklch(0.58 0.22 27), oklch(0.70 0.19 22));
-          --destructive-foreground: light-dark(oklch(0.99 0.005 60), oklch(0.14 0.015 60));
 
           --primary-tint:   color-mix(in oklch, var(--ring) 22%, transparent);
           --accent-tint:    color-mix(in oklch, var(--ring) 14%, transparent);

gallery/public/input.css

@@ -61,6 +61,11 @@
      app/layout.ts so the ring and its halo are the same hue. */
   --color-primary-tint:           var(--primary-tint);
 
+  /* One extra semantic shadcn does not ship: success (a couple of status
+     affordances use it). Added the canonical @theme way, not a parallel
+     vocabulary. */
+  --color-success:                var(--success);
+
   --font-display: var(--font-display);
   --font-sans:  var(--font-sans);
   --font-serif: var(--font-serif);