The dev container was relying on HA's runtime pip-install of manifest.json
requirements, which only fires when the integration is set up and needs
outbound network access at that exact moment; a container that had been
running since before the smartthings-local migration kept the old code
loaded in memory and never went through that install path, so restarting
it failed once it picked up the new manifest.json.
Repurpose the stale MQTT-bridge-era Dockerfile (its own code was already
deleted from this repo) to build on the official HA image with
smartthings-local pre-installed, and point docker-compose.yml at it via
`build: .`. Verified end-to-end: rebuilt the image, recreated the
container, and confirmed both live appliances (fridge, dishwasher)
reconnect and discover entities with no runtime install needed.
Marc Billow