feat(casan): add native plugin facade

docs/packaging/CASAN_PACKAGING_PLAN.md

@@ -9,7 +9,7 @@ contents + maturity: [`packaging/levels.json`](../../packaging/levels.json).
 
 | Edition | Package names | Status | What it is |
 |---|---|:--:|---|
-| **1 — Core Harness** | `casan-core`, `casan-harness` | ✅ implemented | Minimal H1–H7 production runtime plus zero-dependency Local Assurance Viewer: latest/history, interactive H1–H7, H6 and on-demand export |
+| **1 — Core Harness** | `casan-core`, `casan-harness` | ✅ implemented | Minimal H1–H7 production runtime, native Codex/Claude operator façade, plus zero-dependency Local Assurance Viewer: latest/history, interactive H1–H7, H6 and on-demand export |
 | **2 — DevKit / Adoption Kit** | `casan-devkit`, `casan-project-kit` | ✅ implemented | Level 1 + project templates, domain-pack scaffold, Gitea workflow template, harness Dockerfile, install script, adoption/CI/domain-pack guides |
 | **3 — Platform Components** | `casan-platform`, `casan-control-panel` | 🟡 preview | Control Panel, Dashboard, Run History, governed chat MVP and **Evidence Pack Viewer**. Attack Battery Viewer, Gitea evidence publishing, and managed rollout are still pending. |
 | **4 — Enterprise / Governed Console** | `casan-enterprise`, `casan-governed-console` | 📋 future | Promotion layer requiring managed deployment, KMS/Object Lock operations, HA/DR/SLA, external review and compliance/support evidence. |
@@ -42,6 +42,12 @@ Docker images (see `DOCKER_GUIDE.md`): `casan-harness:X.Y.Z` ✅ · `casan-platf
 Every bundle carries `BUNDLE-MANIFEST.txt` + `SHA256SUMS`; preview bundles also carry
 `PREVIEW-INCOMPLETE.txt`.
 
+Core and every cumulative bundle also carry `.codex-plugin/`, `.claude-plugin/`
+and `skills/casan/`. These files expose an optional native `$casan` operator
+surface. They do not install the shared runtime or enable project hooks; the
+production trust path remains global/vendored runtime installation followed by
+`casan init` and client hook review.
+
 ## Production runtime boundary
 
 `packaging/runtime-layout.json` is the canonical allowlist used by macOS/Linux,
@@ -77,6 +83,9 @@ packages/casan-harness/     # L1 core (implemented)
 packages/casan-devkit/      # L2 adoption kit (implemented)
 packages/casan-platform/    # L3 structure-only (preview; README)
 packages/casan-enterprise/  # L4 structure-only (future; README)
+skills/casan/               # native operator skill shared by Codex + Claude
+.codex-plugin/              # Codex plugin manifest
+.claude-plugin/             # Claude plugin + marketplace manifests
 bin/casan                   # CLI
 scripts/package-release.sh  # release packager
 packaging/levels.json       # bundle contents + maturity (source of truth)