dsh-token-use: DeepSeek Harness Real-Time Token Usage and Cost Dashboard

DeepSeek Harness (DSH) adds a new `dsh-token-use` plugin aimed at addressing the difficulty of tracking token consumption through visual dashboards. Integrated into the settings panel, its core features include overview, model, and project statistics, with support for 7/30/90-day trend charts, heat maps, and multi-dimensional filtering. It estimates costs based on DeepSeek’s official pricing (counting only deepseek models) and supports health checks and system operations. The plugin updates data incrementally via an event bus without polling and requires DSH web version ≥ 0.1.0-rc.6.