Fix Dockerfile for NextAuth + Prisma deployment

Add Prisma support to Docker build:
- Run 'prisma generate' during Docker build
- Copy Prisma client and schema to production image
- Remove 'prisma db push' from build script (runs at startup)
- Enable Next.js standalone output mode
- Add db-setup.sh script for runtime migrations

This fixes the deployment failure where Prisma wasn't available.

Co-authored-by: Cursor <cursoragent@cursor.com>

scripts/db-setup.sh

@@ -0,0 +1,7 @@
+#!/bin/sh
+# Run database migrations at container startup
+# This ensures DATABASE_URL is available from Coolify env vars
+
+echo "Running Prisma DB setup..."
+npx prisma db push --accept-data-loss --skip-generate
+echo "Database setup complete!"