Sandbox create fails with HTTP 400 on Docker API 1.52: client hardcodes /v1.54, and the SDK error drops the daemon's reason #457

Version: v1.1.0 (9f97a7e). Ubuntu 24.04.5 (kernel 7.0.0-1014-gcp), Node 24.21.0. Docker 29.1.3 (API 1.52) for the failure, then docker-ce 29.9.2 (API 1.56) for the success.

Repro:

1. Install Docker 29.1.3 (docker version → server API 1.52).
2. LayerFS.open and sandbox.create() with image debian:bookworm-slim (sha256:7ff6ba31527b9e336162fa061746c366c4b2032f4d2cff2078bea43f78efe3f8). No runtime image is needed: the failure comes at the volume step, before any container starts.
3. The SDK rejects with phase: Volume, transfer status: Some(400), an 84-byte error body, and no message text. Separately, direct probes on the Docker socket (POST /v1.54/volumes/create and GET /v1.54/version) each return 400 with the body {"message":"client version 1.54 is too new. Maximum supported API version is 1.52"} plus a newline. That is 84 bytes, the same size as the SDK's error_body.
4. Upgrade to docker-ce 29.9.2 (API 1.56). The same sandbox.create() succeeds. Reproduced on two runs.

Expected: the docs state the minimum Docker API version, the SDK error carries the daemon's message, or the client negotiates the API version.

Actual: the client hardcodes /v1.54. core/crates/layerfs-sandbox/src/backend/docker/container.rs:47 (plain_volume, GET /v1.54/volumes/{name}) and :106–107 (POST /v1.54/containers/create). The SDK error at step 3 does not include the daemon's text, so the reason is visible only by calling the socket directly. The only volume request in LayerFS's source is the GET at container.rs:47; the source has no POST /v1.54/volumes/create, so that probe is not a request LayerFS sends. We infer that the failing request at phase Volume is the :47 GET. We did not observe the SDK's request itself. The 1.54 requirement is mentioned in core/docs/architecture/71-ordinary-engine-runtime-foundation.md; the README and api/README.md mention Docker only in test setup.

Dedupe (Ephemeral-AI-Lab/layerfs, searched 10-26): "too new" 0 hits; "API version" 0 hits; "1.54" 5 hits, none about the Docker API.

Request: document the minimum Docker API version with the install requirements, and have the SDK surface the daemon's error message, or negotiate the API version.

I work on Commonly (commonly.me). Written with AI assistance; the repro was run as described, and the quotes were checked at 9f97a7e.