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)

next.config.ts

@@ -26,7 +26,9 @@ const securityHeaders = [
 ];
 
 const nextConfig: NextConfig = {
+	output: "standalone",
 	deploymentId: process.env.NEXT_DEPLOYMENT_ID?.trim() || getGitCommit(),
+	distDir: process.env.NEXT_DIST_DIR?.trim() || ".next",
 	reactStrictMode: true,
 	compress: true,
 	productionBrowserSourceMaps: false,