dsh-quant-workspace: Self-contained quantization research plugin for DeepSeek Harness

dsh-quant-workspace is a self-contained quantitative research plugin for DeepSeek Harness (DSH), designed to integrate data acquisition, rule-based backtesting, and report generation into a single plugin. It features a built-in Python engine that supports fetching daily data via Yahoo Finance (default 2 years) and provides a `single_ticker` tool for single assets. Core features include: rule-based backtesting (outputting metrics such as individual trades, total return, maximum drawdown, and win rate); generating self-contained interactive HTML reports containing candlesticks, volume, %B, and equity curves, with support for zoom, pan, and crosshair operations; and a strategy registry that allows users to save and reuse verified rule IDs. This plugin strictly maintains a read-only boundary; it does not place orders, modify positions, or require market data keys.