dsh-plugin-dit: Add DIT.ai Dual-Protocol Model Provider to DeepSeek Harness

dsh-plugin-dit is a DeepSeek Harness plugin (current version 0.2.1) developed by cuboteam and based on the MIT License, designed to integrate DIT.ai as a native model provider. The plugin mainly implements three functions: first, it supports DIT.ai as a model source while exposing two sets of APIs, OpenAI Chat Completions (dit) and Anthropic Messages (dit-messages); second, it provides an onboarding flow for the Web profile upon first run to assist users with registration, API Key creation, and credential storage; and third, it supports Native Messages thinking level settings. The plugin does not store API keys itself but instead uses...