The build compose got ROBOCO_EXTERNAL_PR_ENABLED (default true) but the
registry compose's orchestrator env was missed, so a pull-based deploy would
have defaulted it off — inconsistent. Add the same external-PR block so both
deploy paths behave identically.
pr-reviewer-1 was the one agent with no dedicated image and no compose
builder service — it reused roboco-agent-base, which left it absent from the
compose files entirely (so it looked like the PR reviewer simply was not
there). Make it first-class for parity: add docker/agent-pr-reviewer.Dockerfile
(FROM the base — read-only reviewer, no extra toolchain), an
agent-pr-reviewer-image builder service in both compose files and the registry
compose, the image in the release workflow's publish list, and map
pr-reviewer-1 -> roboco-agent-pr-reviewer in the orchestrator plus its
lazy-build dockerfile map. Supersedes the earlier base-reuse mapping.
The orchestrator spawned agents only by bare image names and built any
missing image from source on the host, so a deployment had to carry the
build context and a toolchain — there was no way to just pull and run the
images the release workflow publishes.
Add two settings (default empty = unchanged local-build behavior):
ROBOCO_AGENT_IMAGE_REGISTRY and ROBOCO_AGENT_IMAGE_TAG. When a registry is
set, the orchestrator spawns and ensures {registry}/roboco-agent-*[:tag] and
pulls (never builds) any image it lacks. Also adds the previously-missing
agent-secretary image to the lazy-build map.
Ship docker-compose.registry.yml: a standalone compose that pulls every
published image (GHCR or Docker Hub, pinnable version) and wires the
orchestrator to spawn the matching pre-built agent images. The existing
build compose files are unchanged.