feat: dockerize app and convert to pyproject setup

- Add pyproject.toml with proper metadata and dependency groups
- Create multi-stage Dockerfile for backend
- Add docker-compose.yml with dev/prod profiles
- Create frontend Dockerfile with nginx
- Add .dockerignore for optimized builds
- Update README with Docker instructions and troubleshooting
- Remove requirements.txt in favor of pyproject.toml
- Ensure data persistence with Docker volumes

.dockerignore

@@ -0,0 +1,73 @@
+# Python
+__pycache__/
+*.py[cod]
+*$py.class
+*.so
+.Python
+build/
+develop-eggs/
+dist/
+downloads/
+eggs/
+.eggs/
+lib/
+lib64/
+parts/
+sdist/
+var/
+wheels/
+*.egg-info/
+.installed.cfg
+*.egg
+
+# Virtual environments
+venv/
+env/
+ENV/
+
+# Database
+*.db
+*.sqlite
+*.sqlite3
+
+# Frontend
+node_modules/
+frontend/dist/
+frontend/build/
+
+# IDE
+.vscode/
+.idea/
+*.swp
+*.swo
+*~
+
+# OS
+.DS_Store
+Thumbs.db
+
+# Logs
+*.log
+logs/
+
+# Environment
+.env
+.env.local
+
+# Git
+.git/
+.gitignore
+
+# Documentation
+*.md
+!README.md
+
+# Tests
+tests/
+.pytest_cache/
+.coverage
+
+# Backup tool data
+backups/
+test.db
+backup_tool.db