dsh-sophnet-balance: SophNet Balance Query Plugin

The DeepSeek Harness plugin `dsh-sophnet-balance` is designed to provide developers with real-time monitoring of SophNet balances and usage. It automatically detects the SophNet provider and displays the balance status (green/yellow/red) using a breathing-light indicator on the right side of the input box. Clicking it expands a liquid-glass panel to view detailed billing information, token statistics, and cost breakdowns. The plugin is open-sourced under the MIT License, relies on the `SOPHNET_API_KEY` environment variable, and includes a conflict-handling mechanism. A restart of `dsh web` is required after installation. During use, it supports custom date-range queries, accommodates differences in API response structures, and displays credit limits and outstanding balances, significantly improving the development and debugging experience.