Make the showcase dev tool faithful to staging by construction. Two changes:
1. `showcase test --d5/--d6` now drives the fleet CONTROL-PLANE (producer ->
probe_jobs queue -> worker -> result-aggregator) instead of the legacy
in-process runLevel() driver. The new cli/control-plane-run.ts replicates
the deep/full producer tick exactly as runControlPlane wires it
(createE2eDeepServiceEnumerator / createServiceEnumerator over
createJobProducer + createFleetQueueClient), enqueues one operator-triggered
tick, and polls local PocketBase for the run's terminal cells. The running
worker fleet claims + runs the driver + the aggregator writes the d5/d6
status cells, so the dev tool exercises the IDENTICAL wiring + concurrency
as staging. The old in-process path stays available behind `--direct`.
2. `showcase up --dev` adds a docker-compose.dev.yml overlay that bind-mounts
each integration's source and overrides the run command with a stack-aware
hot-reload entrypoint (shared/dev/dev-entrypoint.sh: uvicorn --reload for
FastAPI agents, langgraph dev for graphs, next dev for the frontend). Edit a
source file and the component reloads in place with no image rebuild. The
built-image mode remains the faithful/staging-equivalent default.