dsh-sonarqube: A Read-Only SonarQube Toolkit for DeepSeek Harness

`dsh-sonarqube` is a web-enabled tool plugin for DeepSeek Harness, designed to allow agents to read code quality data through the SonarQube API. The plugin provides a set of read-only tools, including querying quality gates, searching issues and security hotspots, and retrieving coverage metrics. It supports configuring the SonarQube URL and token via environment variables or a configuration file. The current version is released under the MIT License, supports query operations only, does not allow data modification, and requires SonarQube to use a valid TLS certificate.