feat(devops): improve multi-stage production Dockerfile for NestJS API

- Use pnpm deploy --prod for pruned production node_modules (smaller image)
- Add docker-entrypoint.sh with optional Prisma migration support (RUN_MIGRATIONS)
- Copy generated Prisma client explicitly into production stage
- Add OCI image labels for container registry metadata
- Update .dockerignore: exclude apps/web, libs/ai-services, agent configs, Python artifacts
- Add build directive + RUN_MIGRATIONS env to docker-compose.prod.yml
- Maintain non-root user, dumb-init signal handling, and healthcheck

Co-Authored-By: Paperclip <noreply@paperclip.ing>

.dockerignore

@@ -7,6 +7,7 @@ dist
 .git
 .github
 .husky
+.gitignore
 
 # Documentation and tests
 docs
@@ -30,6 +31,7 @@ playwright-report
 coverage
 .turbo
 .cache
+.nx
 
 # OS files
 .DS_Store
@@ -37,8 +39,22 @@ Thumbs.db
 
 # Docker files (avoid recursive context)
 docker-compose*.yml
+Dockerfile*
 monitoring
 
 # Dev tools
 scripts/backup
 *.log
+
+# Python / AI services (not needed for API build)
+libs/ai-services
+__pycache__
+*.pyc
+.venv
+
+# Frontend (not needed for API build, has its own Dockerfile)
+apps/web
+
+# Agent configs (Paperclip / Claude)
+.claude
+agents