dsh-compat-guard: upgrade gate + compat matrix + lockfile/rollback for DSH's release chaos

[Shizuku-keop]

DSH is moving fast (4 releases in 12 days) and every breaking change costs real data — the rc.8 storage-format change already wiped user sessions with no official migration path. The community has been holding this together with manual discipline.
I built dsh-compat-guard: a zero-dependency CLI + plugin that turns that discipline into tooling.
What it does

• dsh-guard preflight — upgrade gate: per-plugin compatibility against the target DSH version (registry > author dsh.compat metadata > untested), storage-format fingerprint check (zstd/sqlite magic-byte scan, no decoding), and an automatic $DSH_HOME backup. Blocking changes refuse the upgrade (exit 1).
• dsh-guard snapshot / verify / rollback — per-profile dsh.guard.lock.json (exact dsh + plugin versions, integrity, config hashes, storage facts) + tar snapshots. One-command rollback with a safety snapshot first.
• dsh-guard migrate — session migration (sqlite -> zstd JSONL), backup-first, verify-then-rename, unknown formats are backed up and refused, never guessed.
• A machine-readable compatibility matrix: plugins declare dsh.compat, a reusable GitHub Actions workflow + local runner produce per-version install/boot-smoke results into a registry (compat.json) consumed by preflight and rendered as shields.io badges. First results: dsh-better-sidebar & dsh-mnemon pass 8/8 across DSH 0.1.0-rc.7 -> 0.1.1-rc.2.
  Why it fits DSH's model
• Works through the official dsh plugin CLI; the gate wraps plugin add/update/install (dsh-guard dsh -- <args> alias).
• Design constraints verified against source: the launcher has no pre-hook, and the web app owns the profile command line, so the CLI is a standalone bin with a passive boot-time drift probe.
• Registry hosted at github.com/Shizuku-keop/Blue-Whale-Harness/compat (jsDelivr CDN + offline cache).
  Repo: https://github.com/Shizuku-keop/dsh-compat-guard (v0.1.0, MIT, 17 unit tests)
  Compatibility metadata PRs are open upstream: DSH-better-sidebar#384, dsh-mnemon#75.
  Happy to take feedback — especially on the storage-format fingerprint table (rc.7/rc.8 layouts are still unverified, marked unknown rather than guessed).

[Shizuku-keop]

Governance follow-up (upgrade gate, compat matrix, upstream metadata PRs #384 / #75): #4515

[Shizuku-keop]

Second product from the same workshop — dsh-health: session loop-health diagnostics.

Same author as dsh-compat-guard (governance) — this one is the observability layer: zero-dependency CLI + passive live bundle that turns your session log into an auditable health picture.

What it does

• dsh-health report — 7 detectors (oscillation, stall, near-repeat, per-tool, token/cost, compaction) folded into an auditable 0-100 score; every finding carries an action suggestion + evidence seqs
• dsh-health watch / watch --all — real-time alerts while a session runs (live bundle mirrors session/event to JSONL; watch folds only NEW events incrementally)
• dsh-health scan --sort score|tokens — cross-session health ranking
• Reads BOTH JSONL and the new official SQLite store (schema 17), read-only

Design constraints honored

• Pure observer: never injects messages, never touches the model-visible surface (only source.kind === 'user' counts as user input — verified on real sessions where plugin-injected messages outnumber real ones)
• Zero runtime dependencies (node:zlib zstd + node:sqlite builtins)
• Compat-tested against the official sqlite persistence package (fixture built by the official writer from real session events)

61 unit tests; verified live on a real profile (watch streams the session you're running). Repo: https://github.com/Shizuku-keop/dsh-health (also listed in the Blue-Whale-Harness plugin directory)

[Shizuku-keop]

Update — M7 landed: live health cards in the web UI.

The same zero-dependency detectors now run IN the browser: dsh-health-live registers a ConversationNodeDefinition (kind \health) that folds the live session/event stream and renders a health card at each turn end — score badge, findings with action suggestions, and the plugin-activity block (what dsh-mnemon/system-prompt injected, kept visible but never affecting the score).

• Browser and CLI share the same detector code (bundled into client.js via tsdown), so scores agree by construction; verified on a real profile.
• Pure observer throughout: folds + renders only, never injects into the model surface.
• Also fixed a real bug this exposed: oscillation.diagnose was mutating state (severity drifted on repeated diagnoses) — episode counting moved to fold time, diagnose is now read-only.

Still zero runtime deps; the npm name is now \dsh-health-cli\ (the bare name was taken). Repo: https://github.com/Shizuku-keop/dsh-health