feat(packaging): level-based source hub — Core + DevKit packaging, Platform/Enterprise scaffold

Organize CASAN as a reusable source hub with SPLIT releases so downstream adopts only the
level it needs (packaging/levels.json is the single source of truth).

Implemented now:
- Level 1 Core: bin/casan CLI (run/gate/test/verify/reuse/dashboard) + VERSION.
- Level 2 DevKit: packages/casan-devkit (install.sh, Dockerfile.harness, templates:
  project scaffold, domain-pack, gitea-workflow).
- scripts/package-release.sh core|devkit|platform|all-in-one-demo — builds split bundles
  into dist/ (BUNDLE-MANIFEST + SHA256SUMS); platform is stamped PREVIEW/INCOMPLETE;
  enterprise (future) is REFUSED (exit 3, no fake-complete package). Bundles verified:
  extract → bin/casan works, deterministic + domain suites pass, casan reuse VALID.
- docs/packaging: CASAN_PACKAGING_PLAN + ADOPTION + CI + DOMAIN_PACK + GITEA_PACKAGE + DOCKER.

Structure + docs only:
- Level 3 packages/casan-platform (dashboard exists; control-panel/viewers pending).
- Level 4 packages/casan-enterprise (RBAC/tenant/KMS/WORM/approval exist in core; governed
  console pending). No Chat Console/RBAC-console/tenant-console/model-mgmt built in this task.

Harness change (enables extracted bundles to self-resolve): casan-paths.sh + the Python
project_root() walk-ups now accept a second root marker `packages/casan-harness` in addition
to `.specify`, so a freshly-unpacked core/devkit/demo bundle (no `.specify` yet) roots
correctly and creates state on first run. In an adopted repo `.specify` still matches first.
policy-bundle.yaml paths corrected to packages/casan-harness (re-signed). Full gate 64/0/3.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

packages/casan-enterprise/README.md

@@ -0,0 +1,34 @@
+# CASAN Enterprise / Governed Agent Console (Level 4) · **FUTURE / structure-only**
+
+> Status: **FUTURE.** Documented + scaffolded, NOT implemented in this task.
+> `package-release.sh enterprise` **refuses to build** (no fake-complete package) — several
+> building blocks already exist inside the core harness, but the governed console itself
+> does not. Do not ship this as a product yet.
+
+Enterprise governed AI-SDLC console. Packages: `casan-enterprise`, `casan-governed-console`.
+
+## Building blocks that ALREADY exist (in core harness, reusable)
+| Capability | Where |
+|---|---|
+| RBAC | `packages/casan-harness/scripts/bash/rbac-check.py` |
+| Tenant isolation | `tenant-store.sh`, `tenant-paths.sh`, `tenant-registry-verify.sh`, `tenant-crypt.sh` |
+| Approval workflow | `approval-verify.sh`, `approval-sign.sh`, `approval-jwt-mint.py` |
+| KMS | `vault-kms.sh` |
+| WORM ledger | `worm-ledger.py` |
+| Kill-switch / quota | `kill-switch.sh`, `cost-spike-detect.sh` |
+| Loop governance | Plan-17 loop primitives (`loop-*.py`) |
+
+## Components still to build (NOT in this task)
+- Governed Chat Console (Plan-18) · Prompt Mode Router · Model Provider Management
+- Operator mode · Codegen mode · Agent/Skill Registry · policy-versioning UI
+
+## Why it refuses to package
+Per the packaging principle, a level that isn't implemented must **fail clearly** rather
+than emit a fake-complete artifact. Enterprise is `status: future` in
+`packaging/levels.json`, so `scripts/package-release.sh enterprise` exits non-zero with an
+explanation. When the console is built, flip its status to `preview`/`implemented`.
+
+## To implement later
+Sequence: Plan-14 (RBAC console) → Plan-13 (Control Plane) → Plan-18 (Governed Chat
+Console: read-only → operator → chat-as-loop → multi-tenant). Reuse the existing blocks
+above instead of re-writing them.