* ci: cache docker build layers for container_dev
The Go-build image rebuilds its layers on every run; type=gha backend
caching reuses them across runs and platforms.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* ci: pin container build to the pushed sha under layer caching
Dockerfile.go_build clones master inside the image; a cache-from layer
would otherwise keep serving the previous commit's clone and publish
stale code under the dev tag. Passing BRANCH=github.sha makes the clone
layer's key commit-specific while toolchain layers still hit.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
* ci: pass BRANCH via build-args so the per-commit cache key reaches buildx
docker/build-push-action has no `args` input — the BRANCH override was
silently dropped, leaving the build arg at its `master` default and the
clone/checkout layers serving a stale commit under the gha cache.
Generated with [Devin](https://devin.ai)
Co-Authored-By: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
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Co-authored-by: Devin <158243242+devin-ai-integration[bot]@users.noreply.github.com>
