DeepSeek Harness Plugin: session-import-codex

`session-import-codex` is a DeepSeek Harness plugin designed to help developers seamlessly migrate conversation history from the Codex App Server to DSH. It works by reading Codex history and converting it into DSH session events, supporting both a CLI tool and the `/import-codex` chat command. It features deterministic ID generation, idempotency, an offline write workflow, and privacy safety by avoiding access to sensitive files. Before use, ensure the environment meets the required Node.js and pnpm versions, then stop the running process, execute the migration, and restart the service.