dsh-concurrency-meter: DeepSeek Harness Request Concurrency Monitoring

`dsh-concurrency-meter` is a non-intrusive concurrency monitoring plugin for DeepSeek Harness, performing read-only observation solely through the call chain. It provides real-time monitoring, vendor statistics, request details, and threshold alerts, with configurable thresholds and detail display limits. Licensed under the MIT License, the plugin does not store historical data or intercept requests, strictly protects privacy, and enables developers to track workload in real time without disrupting business workflows.