dsh-usage-dock: Per-Session CNY Cost Pill in the DSH Web Interface

The DSH Web UI plugin `dsh-usage-dock` adds a cost pill below the input box, allowing developers to quickly review the cost of a single conversation. Maintained by aliensweety, it supports the `deepseek-official` route and specific models, and automatically calculates and displays estimated fees based on peak/off-peak hours. It is released under the MIT license, does not read logs or access credentials, and clicking the cost pill reveals detailed token usage and cache hit rates. Users can install it via the command line and customize pricing tiers in the Web console.