Add stock market support (S&P 500 top 20)

[naimkatiman]

Description

Extend TradeClaw beyond crypto/forex to support US stock market signals for the top 20 S&P 500 stocks (AAPL, MSFT, GOOGL, AMZN, NVDA, etc.)

Why

Stock support massively expands the user base. Most trading signal tools focus on either crypto or stocks — TradeClaw covering both is a strong differentiator and will attract a much larger audience.

Acceptance Criteria

• Add 20 stock assets to the asset registry
• Integrate a free stock data API (Yahoo Finance, Alpha Vantage free tier, or Twelve Data)
• Apply existing signal engine (RSI, MACD, EMA) to stock data
• Add "Stocks" tab/filter on the dashboard
• Handle market hours (show "Market Closed" outside trading hours)

Tech Notes

• Asset registry in packages/core/src/assets.ts
• Data fetcher pattern in packages/core/src/data/
• Consider using yahoo-finance2 npm package (MIT licensed, no API key needed)

Getting Started

git clone https://github.com/naimkatiman/tradeclaw.git
cd tradeclaw && npm install && npm run dev

Difficulty: Medium-Hard | Area: Core Engine + Data Integration