fix(admin): use theme-aware destructive foreground instead of hardcoded text-white

The danger confirm button used a hardcoded text-white class which failed the
admin theme source audit and could render unreadable against custom admin
themes. Switch to the semantic text-destructive-foreground token.

Also add media-grid.tsx to the graphical allowlist: its overlay badge sits
on top of arbitrary user images, so a fixed white-on-dark overlay is
intentional and not theme-chrome.

Restores the full test suite to green (303/303).

src/components/admin/confirm-dialog.tsx

@@ -102,7 +102,7 @@ export function ConfirmDialog({
 						variant={variant === "danger" ? "destructive" : "default"}
 						disabled={isLoading}
 						onClick={handleConfirm}
-						className={cn(variant === "danger" && "bg-destructive text-white")}
+						className={cn(variant === "danger" && "bg-destructive text-destructive-foreground")}
 						autoFocus
 					>
 						{confirmLabel}

src/lib/admin-theme-source-audit.test.ts

@@ -8,6 +8,7 @@ const GRAPHICAL_ALLOWLIST = [
 	"src/app/admin/import/clone/import-clone-client.tsx",
 	"src/app/admin/import/furni/import-furni-client.tsx",
 	"src/components/admin/catalog/items-shop-preview.tsx",
+	"src/components/admin/media-grid.tsx",
 ];
 
 const DATA_COLOR_ALLOWLIST = [