Add AssistantAgent about repo: https://github.com/spring-ai-alibaba/AssistantAgent

[canfuu]

Fixes: #[Add issue number here]

Changes:

Github Repo: https://github.com/spring-ai-alibaba/AssistantAgent

Added the Assistant Agent documentation module (agents-docs/assistantagent/), including the following content:

1. Quick Start Guide (quick-start.md)

   • Project Introduction: Introduces Assistant Agent as an enterprise-grade intelligent assistant framework built on Spring AI Alibaba
   • Core Capabilities: Code-as-Action paradigm, secure sandbox, multi-dimensional evaluation, dynamic prompts, experience learning, etc.
   • Use Cases: Intelligent customer service, operations assistant, business assistant
   • Quick Start Guide: Prerequisites, clone & build, configuration and startup steps
   • Usage Methods: Chat UI for visual conversation and API integration
   • Knowledge Base Integration: Mock implementation and real knowledge base integration guide
   • SPI Extension Points: SearchProvider, ReplyChannelDefinition, CodeactTool, etc.
   • Secondary Development Guide and Roadmap

2. Secondary Development Guide (secondary-development.md)

   • Detailed secondary development documentation

3. Features Module Documentation (features/)

   • Detailed documentation for each feature module

4. Related Image Resources (images/)

   • Supporting images for documentation

Screenshots of the change:

After adding the documentation, users can view the complete Assistant Agent usage guide on the website, including:

• Introduction to core capabilities and applicable scenarios
• Step-by-step quick start guide from scratch
• Chat UI visual conversation interface demo
• API integration code examples
• Knowledge base integration and SPI extension development guide