Spec can override container images:
image-overrides:
dumpster-kubo: ghcr.io/.../dumpster-kubo:test-tag
Merged with CLI overrides (CLI wins). Enables testing with
GHCR-pushed test tags without modifying compose files.
Also reverts the image-pull-policy spec key (not needed —
the fix is to use proper GHCR tags, not IfNotPresent).
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>