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/api/Dockerfile

@@ -0,0 +1,25 @@
+FROM node:20-alpine
+
+# Install git for repository operations
+RUN apk add --no-cache git
+
+# Create app directory
+WORKDIR /app
+
+# Copy package files
+COPY package*.json ./
+
+# Install dependencies
+RUN npm ci --only=production
+
+# Copy app source
+COPY src/ ./src/
+
+# Create directories
+RUN mkdir -p /app/mindmaps /app/logs
+
+# Expose port
+EXPOSE 8080
+
+# Start the server
+CMD ["npm", "start"]