Finish SAND-WP-0002: remote smoke, podman-compose, HTTP stub

- T10 smoke passed on CoulombCore (sand-boxer self-deploy, sandbox 4e542c51)
- Add e2e smoke compose, scripts/smoke-compose-e2e.sh, make smoke-remote
- Support SANDBOXER_COMPOSE_CMD for podman-compose hosts
- FastAPI v0 stub at sandboxer.api.app; migration gaps doc
- Mark workplan finished (all 10 tasks done)

SCOPE.md

@@ -120,14 +120,14 @@ Additional boundaries:
 
 - **Status:** bootstrap — repo registered with State Hub; charter written;
   implementation not started
-- **Implementation:** ~0% — no CLI, API, profiles, provisioner, or tests in tree
+- **Implementation:** v0 — CLI, profiles, `ext.compose-ssh`, State Hub events, HTTP stub
 - **Docs:** `INTENT.md` (charter, 2026-06-21); `README.md` (one-liner);
   `AGENTS.md` and `.custodian-brief.md` (State Hub integration, generated)
 - **Registry:** scaffold present (`registry/indexes/capabilities.yaml` empty;
   `registry/capabilities/` placeholder); domain in index still `helix_forge`
   from scaffold — needs alignment to `infotech`
-- **Workplans:** `SAND-WP-0001` finished; `SAND-WP-0002` active;
-  `SAND-WP-0008` proposed (host telemetry / self-canary)
+- **Workplans:** `SAND-WP-0001` finished; `SAND-WP-0002` finished;
+  `SAND-WP-0008` ready (host telemetry / self-canary)
 - **Lineage (external, not yet migrated):** `the-custodian/e2e-framework/`
   (CUST-WP-0028, completed) and `infra/build-machines/` (CUST-WP-0032)