Add AShareHub Chinese market data skill

[ChuYiCui1]

Summary

• Adds the official AShareHub Agent Skill to the finance skills section
• Covers Chinese A-share and ETF prices, fundamentals, capital flows, financial statements, and technical indicators
• Uses the documented AShareHub API and Python SDK; the free tier includes 100 requests/day

Runnable example

Use AShareHub to fetch the latest CSI 300 daily prices and return the results as a pandas DataFrame.

Skill: https://github.com/ChuYiCui1/AshareHub-skills
Docs: https://asharehub.com/en/skill