feat: add Docker deployment support

- Add multi-stage Dockerfile for Next.js standalone build
- Add docker-compose.yml with app and MySQL 8.0 services
- Add .dockerignore for optimized builds
- Update next.config.ts with standalone output

.dockerignore

@@ -0,0 +1,61 @@
+# Dependencies
+node_modules
+.npm
+
+# Next.js build output
+.next
+out
+build
+
+# Git
+.git
+.gitignore
+
+# Environment files
+.env
+.env.local
+.env.*.local
+
+# IDE
+.idea
+.vscode
+*.swp
+*.swo
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+npm-debug.log*
+yarn-debug.log*
+yarn-error.log*
+
+# Test
+coverage
+
+# Docker
+docker-compose*.yml
+Dockerfile*
+.dockerignore
+
+# Data files (keep structure but ignore content)
+data/*
+
+# env.docker (template, not actual env)
+.env.docker
+
+# Misc
+README.md
+AGENTS.md
+*.md
+
+# TypeScript
+*.tsbuildinfo
+next-env.d.ts
+
+# Debug
+npm
+pnpm-lock.yaml
+yarn.lock