Enable linux/arm64 (multi-arch) companion images

[antoinetoussaint-byte]

All six service agents now publish linux/arm64 (service-go v0.0.43, service-python v0.0.57, service-nextjs v0.0.147, service-rust v0.0.35, service-swift v0.0.18, service-generic v0.0.34), so the CLI can now safely build/publish arm64 companions — an arm64 companion can resolve every language agent.

Tasks

• Broaden / drop the --platform linux/amd64 pin in .github/workflows/companions.yaml (line 75: codefly companion publish --all --platform linux/amd64 ...) so companions publish multi-arch (or arm64) rather than amd64-only.
• Add a CI check that a linux/arm64 companion can resolve every language service agent. This guards the live footgun where codefly companion build/publish on an Apple Silicon Mac defaults to arm64 (dockerArch() → arm64); before the agents shipped arm64 that produced a companion that couldn't run a single language service.

Not applicable (investigated)

The parent issue's "bump the pins in pkg/sourceworkspace/source.go" item does not apply: the CLI does not pin service-agent versions there — source.go only sets an ephemeral source-workspace Version: "0.0.0". No pin bump needed.

Related

Completes the companion side of codefly-dev/core#346 (service-agent arm64 releases are done).

[antoinetoussaint-byte]

Blocked — the six linux/arm64 agent releases have not shipped, so tasks 1 & 2 cannot be done safely yet.

I verified the release assets for the latest tag of each service agent. None ship a linux_arm64 binary — every one publishes only darwin_amd64, darwin_arm64, and linux_amd64:

Agent	Pinned in source.go	Latest release	ships linux_arm64?	arm64 issue
go	0.0.33	0.0.41	no	#46 open
python	0.0.52	0.0.55	no	#72 open
nextjs	0.0.141	0.0.145	no	#95 open
rust	0.0.29	0.0.29	no	#27 open
swift	0.0.16	0.0.16	no	#14 open
generic	0.0.26	0.0.32	no	#41 open

All six blocking issues are still open. Consequently:

• Task 1 (bump pins): the guard clause "only if versions roll as part of the arm64 releases" is not satisfied. The newer tags exist but add unrelated feature changes, not arm64 — bumping now would not advance arm64 support.
• Task 2 (drop --platform linux/amd64): the precondition "now that every language agent resolves on arm64" is false. Dropping the pin now would let an arm64 runner (or any Apple Silicon codefly companion publish) build a companion that cannot run a single language service — the exact footgun this issue warns about.
• Task 3 (CI check that a linux/arm64 companion resolves every agent): as framed it would fail today, since arm64 agents don't exist. It should land alongside/after the arm64 rollout so it goes green rather than red.

No code changed. This issue should be picked back up once the six per-repo linux/arm64 releases land (i.e. when each latest release includes a service-*_<ver>_linux_arm64.tar.gz asset). At that point: bump the pins in pkg/sourceworkspace/source.go to those releases, broaden/drop the --platform linux/amd64 pin in .github/workflows/companions.yaml, and add the arm64-resolution CI check.

Separately worth noting for whoever picks this up: the live footgun is real today — on Apple Silicon, codefly companion build/publish with no --platform defaults to linux/arm64 via dockerArch() and silently produces a broken companion. A build-time guard that rejects arm64 companions until the agents ship arm64 could protect users in the interim, but it's out of scope for this "catch up once unblocked" issue and was intentionally not added here.