Reaping: sandbox orphan reaper + DB expiry/retention sweeper + volume-init retry

Closes the cleanup gaps found in review (latent today; bites under load/crashes).

Sandbox containers (cm-sandbox / cm-runtime):
- label every sandbox `clawmates.sandbox={agent|browser}` at create
- SandboxDriver::list_managed(kind) (Docker label filter + K8s label selector)
- SandboxManager::reconcile_orphans(ttl) + spawn_reaper: removes engine
  containers no live handle owns (ZERO = all)
- boot reconciliation (every pre-existing sandbox is an orphan from a dead
  process) + periodic reaper (5m interval / 10m TTL)
- SIGTERM graceful drain: serve().with_graceful_shutdown → shutdown() both
  managers so a redeploy can't leak; destroy errors now logged not swallowed

DB expiry/retention (cm-db cleanup.rs + cm-api cleanup_sweeper, hourly):
- expire auth_sessions + oauth_states past expires_at (security)
- prune sent outbox(7d), run_events(14d), routine_runs(30d), terminal
  topology_runs(90d), consumed execution_grants(7d)

Compose: volume-init restart "no" → on-failure:5 (retry instead of wedging boot).

Co-Authored-By: Claude Opus 4.8 <[email protected]>

.sqlx/query-da095f50f527dd650bbf3cf76936366f03865a8b0d456d1d85ad8c56cc1ab7cc.json

@@ -0,0 +1,12 @@
+{
+  "db_name": "PostgreSQL",
+  "query": "DELETE FROM auth_sessions WHERE expires_at < now()",
+  "describe": {
+    "columns": [],
+    "parameters": {
+      "Left": []
+    },
+    "nullable": []
+  },
+  "hash": "da095f50f527dd650bbf3cf76936366f03865a8b0d456d1d85ad8c56cc1ab7cc"
+}