dsh-stock-lookup: Stock Resolution and Market Quote Lookup for DSH Agents

`dsh-stock-lookup` is a DeepSeek Harness plugin that enables agents to directly retrieve real-time financial data. It includes two tools: `stock_resolve`, which resolves a company name or ticker code to a stock symbol and provides an SEC EDGAR link; and `stock_profile`, which retrieves real-time stock quotes, company profile, and industry information. The plugin requires no API key, relies on Yahoo Finance and SEC data, is simple to configure, and is suitable for developing agents that need financial data analysis capabilities.