dsh-tier-router: Hierarchical Model Routing for DeepSeek Harness

`dsh-tier-router` is a hierarchical model routing plugin for DeepSeek Harness (DSH), designed to optimize cost and efficiency through "premium-tier" and "economy-tier" strategies. The premium-tier models handle complex tasks such as planning, architecture, and review, while the economy-tier models manage routine implementations. Core features include automatic hierarchical routing (defaulting to `auto` mode), session-level scope switching, on-demand consultant and review tools, automatic escalation on failure, ordered fallback chains, dynamic adjustment of reasoning intensity, gating for high-impact operations, and hierarchical delegation to sub-agents. The plugin supports flexible configuration of models, effort levels, and sub-agent strategies via `/tier` series commands, with both persistent and temporary configuration capabilities. Released under the MIT license, installation requires meeting specific Node.js version requirements and syncing to the DSH discovery root directory. It is suitable for applications needing