Add WebSocket real-time quote subscription support

[Claude]

Implements WebSocket-based quote subscriptions for efficient real-time market data updates, as an alternative to the existing poll-based track file approach.

Changes

• New subscription manager (internal/market/subscribe.go)

  • Manages WebSocket quote subscriptions via QuoteContext.Subscribe()
  • Handles real-time push callbacks with OnQuote() handler
  • Thread-safe subscription state tracking
  • Automatically updates overview.json and overview.txt on price changes

• File-based subscription interface

  • quote/subscribe/ - Create files to subscribe (e.g., touch quote/subscribe/AAPL.US)
  • quote/unsubscribe/ - Create files to unsubscribe
  • Controller processes requests each polling cycle and cleans up files after processing

• Controller integration

  • Initialize subscription manager on startup
  • Process subscription requests in main control loop alongside existing track-based polling
  • Both methods coexist without interference

• Documentation improvements

  • Added pagination examples for viewing large data files to prevent context window overflow
  • Includes jq slicing for K-line arrays, tail/head/sed for beancount ledger
  • Clarifies which files are small (safe for cat) vs large (require pagination)

Usage

# Subscribe to real-time quotes
touch fs/quote/subscribe/AAPL.US
touch fs/quote/subscribe/700.HK

# Quotes auto-update on price changes
cat fs/quote/hold/AAPL.US/overview.json

# View large files with pagination
jq '.[0:10]' fs/quote/hold/AAPL.US/D.json      # First 10 K-lines
tail -50 fs/trade/beancount.txt                 # Last 50 ledger entries

# Unsubscribe when done
touch fs/quote/unsubscribe/AAPL.US

WebSocket subscription provides low-latency real-time updates for monitoring positions and watchlists, while track files remain available for one-shot fetches of historical data (K-lines, intraday).

[JetSquirrel]

如果文件中堆积了很多数据，模型在查看的时候，会全部 stdout 出来，然后把上下文窗口占满

应该是由分页机制，cat 设置数据长度 limit，可以通过参数查看下一页

[Claude]

Added pagination examples throughout the documentation to prevent context overflow:

• K-line data: jq '.[0:10]' file.json for slicing arrays
• Beancount ledger: tail -50, head -50, sed -n '100,150p' for viewing ranges
• PnL/Portfolio: jq '.positions[0:5]' when many holdings

Small files like overview.json are noted as safe for direct cat viewing.

Commit: 9d894ab

[JetSquirrel]

@claude[agent]