dsh-delete: A Recoverable Conversation Deletion Plugin for DeepSeek Harness

`dsh-delete` is a Memory plugin for DeepSeek Harness (DSH) intended to solve the problem that append-mode session logs cannot be safely deleted. It adopts a two-phase strategy: during runtime it hides a session and adds it to a deletion queue, and during restart it atomically moves the logs to a trash directory. The plugin provides two deletion methods—a UI menu and a command-line interface that requires entering `CONFIRM`—and supports a JSONL backend as well as absolute-path configuration. When DSH is restarted, logs are moved into a recoverable trash directory, allowing administrators to decide on a cleanup policy. Restoring the data requires stopping the service before performing the operation.