DeepSeek Harness Plugin: OpenCode Go Quota Floating Window

The `dsh-plugin-opencode-go-quota` plugin is designed to address the pain point for DeepSeek Harness (DSH) users who manually check OpenCode Go plan quotas. It provides a draggable floating window in the bottom-right corner of the Web interface that displays real-time quota information across three periods: a rolling 5-hour window, weekly, and monthly. Core features include multi-period display, automatic refresh every 5 minutes, smart show/hide (shown only for opencode-go series models), and multi-account support. Installation requires adding the package via CLI and registering it in the configuration file, with support for reading authentication information from environment variables or the OpenCode CLI.