fix: include prisma directory in Docker runtime stage

[riba2534]

Problem

When self-hosting happy-server using Docker, the container starts successfully but fails with database errors:

Invalid `prisma.session.findMany()` invocation:
The table `public.Session` does not exist in the current database.

This happens because the Dockerfile's runner stage doesn't include the prisma directory, making it impossible to run prisma migrate deploy inside the container to initialize the database.

Root Cause

The official Dockerfile only copies these files to the runtime stage:

• tsconfig.json
• package.json
• node_modules
• sources

But it's missing prisma/, which contains schema.prisma and migration files needed for database setup.

Solution

Add one line to copy the prisma directory in the runtime stage:

COPY --from=builder /app/prisma ./prisma

This allows the container to:

1. Run prisma migrate deploy to initialize the database
2. Properly support self-hosted deployments

Testing

After this fix:

1. Build the Docker image
2. Run with docker-compose
3. Execute docker exec <container> yarn prisma migrate deploy
4. All 36 migrations apply successfully
5. Service starts without database errors

Impact

• Minimal change (1 line added)
• No performance impact
• Enables proper self-hosting workflow
• Maintains the multi-stage build optimization

Co-Authored-By: Claude Sonnet 4.5 noreply@anthropic.com