output: "export" produces pure static HTML with no server at runtime, so
the contact form's Server Action (src/actions/sendEmail.ts, nodemailer/SMTP)
can never execute under it - Next.js itself refuses to build with a Server
Action present under output: "export". The deploy architecture is being
switched to a Node standalone runtime (see doormile-build) instead, which
supports the existing Server Action unchanged.
output: "standalone" (a8f4b23) produces a Node server bundle with no
server.js at the path the deploy Dockerfile expects. The deploy repo's
Dockerfile now runs nginx serving static files (d808317), which requires
a static export (out/), not a standalone server bundle.
