feat: Add Nanaxe server with Docker, GitHub Actions CI/CD, and auto-deployment

- Add complete server infrastructure with Gitea, API, PostgreSQL
- Implement Obsidian-compatible markdown mindmap converter
- Add Flutter service for server synchronization
- Configure GitHub Actions for automated build and deploy
- Add production docker-compose with health checks
- Include VPS setup and deployment scripts
- Add comprehensive deployment documentation

server/.env.example

@@ -0,0 +1,21 @@
+# Nanaxe Server Configuration
+# Copy this file to .env and update the values
+
+# Domain configuration
+GITEA_DOMAIN=your-domain.com
+
+# Gitea Configuration
+GITEA_TOKEN=your_gitea_api_token_here
+
+# Security
+JWT_SECRET=your-super-secret-jwt-key-change-in-production
+
+# WebDAV (optional)
+WEBDAV_USER=admin
+WEBDAV_PASSWORD=secure_password_here
+
+# Database (change in production!)
+POSTGRES_PASSWORD=change_this_password
+
+# API Configuration
+API_PORT=8080