dsh-session-resilience: DSH Safe Restart and Policy-Based Session Recovery

`dsh-session-resilience` is a configuration plugin for DeepSeek Harness (DSH), designed to address session interruptions caused by host restarts, network disruptions, or token limits. Through safe restarts, token-aware reconnection, and policy-based session recovery, it ensures that DSH can seamlessly resume tasks after interruptions. Its core features include local control, four preset recovery strategies (Safe, Balanced, Long task, and Manual), and native tool-calling support. After installation, users can manage session recovery uniformly via the settings interface; the system reports readiness only after successful connection verification, significantly improving the stability of agent task execution.