Add additional Dumpling AI API endpoints

[codegen-sh]

This PR adds support for the following Dumpling AI API endpoints:

• scrape: Extract data from a specified URL
• crawl: Crawl a website and return structured content
• extract-document: Extract structured data from document files
• extract-image: Extract structured data from image files
• doc-to-text: Convert PDF or DOCX documents into plain text
• screenshot: Capture a screenshot of a specified URL
• generate-ai-image: Generate high-quality AI images
• extract-video: Extract structured data from video files

Each endpoint is implemented following the same pattern as the existing endpoints, with proper error handling and response formatting. The README has also been updated to include the new endpoints and example usage.

These additions complete the implementation of all available Dumpling AI API endpoints, providing a comprehensive MCP server for use with Claude and other AI assistants.