Fix Docker build: ship entrypoint.sh as a real file instead of heredoc COPY

The classic Docker builder (used by docker-build.yml on the host runner)
does not support heredoc COPY syntax, which caused 'COPY failed: no source
files were specified'. Replace the heredoc with a checked-in entrypoint.sh
copied normally.

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

Dockerfile

@@ -57,14 +57,7 @@ EXPOSE 3000
 ENV PORT=3000
 
 # script to run migrations before starting
-COPY --chown=nextjs:nodejs <<EOF /app/entrypoint.sh
-#!/bin/sh
-set -e
-echo "Running prisma db push..."
-npx prisma db push --accept-data-loss
-echo "Starting server..."
-node server.js
-EOF
+COPY --chown=nextjs:nodejs entrypoint.sh /app/entrypoint.sh
 
 RUN chmod +x /app/entrypoint.sh