[Feature Request] Align Java Runtime with Python: Implement Built-in Tools (RAG, Payment, etc.)

### Description

The **AgentScope Runtime Python** provides a set of **built-in, production-ready tools** that greatly accelerate agent development, including:

- **RAG (Retrieval-Augmented Generation)**: Document ingestion, vector search, and context-augmented LLM calls
- **Payment Tool**: Secure payment initiation and status query (e.g., via Alipay) ,etc.

However, the **Java runtime currently lacks equivalent built-in tool implementations**, forcing Java users to:

- Re-implement common functionality from scratch
- Maintain custom wrappers with inconsistent interfaces
- Miss out on standardized observability, error handling, and security patterns provided in the Python version

To ensure **feature parity**, **developer experience consistency**, and **enterprise readiness**, we propose implementing the same set of built-in tools in the Java runtime.