feat: add code agent sandbox skeleton

scripts/src/help.ts

@@ -39,6 +39,7 @@ export function rootHelp(): unknown {
       { command: "deploy check|plan|apply [--file deploy.json|--env dev|prod] [--service id] [--commit full-sha] [--dry-run] [--force]", description: "Reconcile services from a repo+commit manifest; --env reads origin/master:deploy.json environments and applies supported dev target-side rollouts or reviewed D601 registry artifact consumers. code-queue artifact consumption is dev-only." },
       { command: "dev-env validate|prewarm-images", description: "Validate D601 unidesk-dev guardrails or prewarm dev foundation images into native k3s containerd through a bounded async job." },
       { command: "artifact-registry plan|render|status|health|install|deploy-backend-core|deploy-service", description: "Manage the D601 host-managed CNCF Distribution registry and run pull-only artifact CD for supported services, including D601 direct, k3s-managed, and code-queue dev-only consumers." },
+      { command: "code-agent-sandbox", description: "Independent Code Agent Sandbox service skeleton for adapter, mode, and credential-boundary diagnostics." },
       { command: "schedule list|get|runs|run|delete", description: "Manage backend-core scheduled tasks and run history; schedule run <id> supports --wait-ms N." },
       { command: "schedule upsert-pgdata-backup [--time HH:MM] [--remote-base /SERVER_DATA/UNIDESK_PG_DATA]", description: "Create or update the daily PGDATA physical backup task that uploads monthly rotated archives to Baidu Netdisk." },
       { command: "codex deploy <commitId> [--provider-id D601] [--timeout-ms N]", description: "Disabled legacy Code Queue deploy path; use the dev-only artifact consumer instead." },