fix(theme): R10 S1 follow-ups — dedicated info token + restore collapsed hovers

- Add --info/--info-fg (blue; dark #60a5fa / light #2563eb) so info notifications
  stop borrowing --accent, which collided with a status colour in schemes whose
  accent shares its hue (YouTube red = error, Slate orange = warn, Matrix/Forest
  green = success). Toaster info tone accent -> info.
- Restore hover feedback the codemod flattened: 'bg-X ... hover:bg-X' /
  'text-X ... hover:text-X' collapsed to a no-op once both shades mapped to one
  shadeless token. Reuse the house hover:opacity-{80,90} idiom (ConfirmProvider
  danger button, DownloadCenter error link).

frontend/src/components/ConfirmProvider.tsx

@@ -118,7 +118,7 @@ export function ConfirmProvider({ children }: { children: ReactNode }) {
                   multi ? "w-full" : ""
                 } ${
                   c.danger
-                    ? "bg-danger text-danger-fg hover:bg-danger"
+                    ? "bg-danger text-danger-fg hover:opacity-90"
                     : "bg-accent text-accent-fg hover:opacity-90"
                 }`}
               >