dsh-session-integrity: DeepSeek Harness Session Integrity and Recovery Plugin

dsh-session-integrity is a plugin for repairing DeepSeek Harness (DSH) session integrity failures. When abnormal tool calls cause missing `tool/result` entries, the history develops "transcription defects," leading to subsequent request failures. The plugin scans the session to distinguish visible defects from hidden gaps and provides a safe recovery plan. It uses the Fork API to create a new session instead of directly modifying source data, ensuring data non-destructiveness, and supports offline CLI diagnostics, privacy reports, and web-interface continuation.