dsh-agent-pricing: DeepSeek Harness Real-time Session Cost Preview

`dsh-agent-pricing` is an MIT-licensed plugin developed specifically for the DeepSeek Harness Web profile, aiming to address issues regarding token consumption and cost tracking in chat-based development. The plugin offers three core features: first, it displays the cumulative cost of the current session in real-time beneath the input area, refreshing every 5 seconds and supporting CNY/USD switching; second, it presents an overlay for today's usage, including token breakdown, hourly bar charts, and model breakdowns; and third, it registers `price_estimate` and `session_cost` tools, enabling the Agent to autonomously query estimated prices or full session costs. Prices are synchronized from the DeepSeek official page, support peak-valley pricing awareness, and automatically fall back to repository or built-in prices if scraping fails.