fix: harden update pipeline and restore a clean production build

- update-Nitrov3.sh: build CMS into .next-staging and swap atomically so a
  failed build never takes the live site down; auto-merge new variables
  from .env.example; validate env for duplicates/broken lines; restart the
  emulator/CMS only when rebuilt or unhealthy; fix step renumbering
- next.config.ts: support NEXT_DIST_DIR for staged production builds
- fix all TS errors (unused imports, missing tryDownloadCandidates helper)
  so tsc and the production build pass clean
- add Dockerfile/.dockerignore and switch docker-compose to a CMS container
- include prevailing UI/refactor changes (SurfaceCard, ticketing, tsconfig)

src/components/ui/card.tsx

@@ -48,19 +48,6 @@ function CardDescription({ className, ...props }: React.ComponentProps<"div">) {
 	);
 }
 
-function CardAction({ className, ...props }: React.ComponentProps<"div">) {
-	return (
-		<div
-			data-slot="card-action"
-			className={cn(
-				"col-start-2 row-span-2 row-start-1 self-start justify-self-end",
-				className,
-			)}
-			{...props}
-		/>
-	);
-}
-
 function CardContent({ className, ...props }: React.ComponentProps<"div">) {
 	return (
 		<div
@@ -71,22 +58,4 @@ function CardContent({ className, ...props }: React.ComponentProps<"div">) {
 	);
 }
 
-function CardFooter({ className, ...props }: React.ComponentProps<"div">) {
-	return (
-		<div
-			data-slot="card-footer"
-			className={cn("flex items-center px-6 [.border-t]:pt-6", className)}
-			{...props}
-		/>
-	);
-}
-
-export {
-	Card,
-	CardAction,
-	CardContent,
-	CardDescription,
-	CardFooter,
-	CardHeader,
-	CardTitle,
-};
+export { Card, CardContent, CardDescription, CardHeader, CardTitle };