dsh-reconnect: Secure Retry Plugin for DeepSeek Harness Model Requests

dsh-reconnect is a Host-side plugin for DeepSeek Harness (DSH) designed to automatically retry model requests when failures occur due to temporary network or service issues. It listens for the `agent/request-error` event and takes over after the built-in retry strategy fails. For recoverable issues such as rate limiting, timeouts, 5xx errors, and disconnections, it employs an exponential backoff algorithm to resend requests, thereby preventing the interruption of agent steps. The plugin supports configuring a local backoff cap (default 60s) and prioritizes respecting the Provider's `Retry-After` directive. For quota exhaustion (QUOTA), retrying is disabled by default; unknown errors retry infinitely by default (configurable limit), while unrecoverable errors such as authentication failures and invalid parameters terminate immediately. The plugin provides a unified settings card and YAML configuration.