dsh-session-health: Read-Only Health Diagnostics for DSH Multi-Frame Zstd Session Files

dsh-session-health is a DSH admin-security plugin maintained by omdsh-dev. It performs frame-level read-only scans on multi-frame zstd session files located under $DSH_HOME/sessions, detecting torn, corrupted, empty sessions, and stray files. The plugin registers the `session_health` tool, which outputs JSON reports and cleanup recommendations. It supports three actions: scan, file, and stats, with an optional deep analysis mode. It can be installed via `dsh plugin add` in DSH 0.1.0-rc.8 and complements the dsh-session-repair-skill. Licensed under MIT.