feat: add Docker containerization with multi-stage build

- Create production-ready Dockerfile with multi-stage build
- Add CGO support for SQLite driver compilation
- Implement security best practices with non-root user
- Add health checks with proper API version headers
- Create .dockerignore for optimized build context
- Support both SQLite and MySQL in containerized environment
- Include volume mounting for data persistence

🤖 Generated with [Claude Code](https://claude.ai/code)

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

.dockerignore

@@ -0,0 +1,39 @@
+# Git
+.git
+.gitignore
+
+# Documentation
+README.md
+*.md
+
+# Docker
+Dockerfile
+.dockerignore
+
+# Build artifacts
+server
+*.exe
+
+# Development files
+.vscode/
+.idea/
+
+# Local config and data
+config.json
+*.db
+data/
+
+# Test files
+*_test.go
+test*
+
+# Temporary files
+*.tmp
+*.log
+
+# OS files
+.DS_Store
+Thumbs.db
+
+# Dependencies (will be downloaded)
+vendor/