Fix README enclave build steps and import example

[nickpell]

Summary

• enclave/Dockerfile copies a prebuilt ./bin/tee-auction-enclave, so the README's docker build fails on a clean checkout with "/bin/tee-auction-enclave": not found. The README now runs the go build command from .github/workflows/docker.yml first, with the same flags and the workflow's default GOARCH=arm64. The docker build line gets --platform linux/arm64, so the image platform matches the binary, as the workflow's platforms input does. One line gives the amd64 variant that the workflow's manual dispatch offers. On an amd64 Linux host, the image's RUN steps need arm64 emulation, so the README gives the tonistiigi/binfmt command that docker/setup-qemu-action runs in the workflow.
• The usage example no longer imports github.com/cloudx-io/openauction/enclave. That directory is package main, and Go rejects the import: is a program, not an importable package.
• .gitignore now ignores /bin/, so the README build leaves git status clean. No tracked file lives under a bin/ directory.
• Fix README enclave build steps openarbiter#38 makes the same build-step fix in openarbiter. The two PRs do not depend on each other.

Notes for reviewers

The README's docker build line matched the original multi-stage Dockerfile. #7 moved compilation into docker.yml to make image builds faster and more cacheable, and the README kept the old step. This PR keeps the prebuilt-binary design and documents the step it needs.

Pre-merge checklist

• Documented build steps succeed from a clean checkout: the two README commands, run verbatim under bash, build a static linux/arm64 ELF binary and a linux/arm64 image. The amd64 variant builds a static x86-64 binary and a linux/amd64 image.
• The README go build line is byte-identical to the one in docker.yml, with ${ARCHITECTURE} at its arm64 default.
• The trimmed import block (core, enclaveapi) compiles in a scratch module that replaces github.com/cloudx-io/openauction with this branch. With enclave added back, the build fails as described above.
• Go and Docker Build workflows green on this branch: lint, test and Ratchet Lint pass, and Docker Build run 36878528554 built the head commit without publishing. Neither workflow runs the README commands.
• After the README build, git status --porcelain prints nothing, and git check-ignore matches the binary to /bin/.
• Diff contains no unintended changes: README.md and .gitignore only.

Not run: the image itself, which needs a Nitro Enclave host, and the emulation command, which needs an amd64 Linux host. The EIF build runs only on main.

Post-deploy/apply verification

• The next Build EIF run on main after the merge is green, including update-pcrs

[Copilot]

Copilot review overview

🟢 Approval recommended

The documentation now accurately reflects the Dockerfile and workflow behavior.

Review effort: Balanced
Findings: None

What changed in this PR

Updates README instructions to align with the current prebuilt enclave binary workflow.

Changes:

• Removes the invalid package main enclave import.
• Documents arm64 binary and Docker image builds, including amd64 substitutions.

File	Description
README.md	Corrects imports and enclave build instructions.

---

💡 Add a code-review agent skill or configure MCP servers for context-aware, tailored reviews. Learn more in the docs.

[Copilot]

Copilot review overview

🟢 Approval recommended

The documentation accurately matches the Dockerfile and workflow behavior.

Review effort: Balanced
Findings: None

[Copilot]

Copilot review overview

🟡 Changes recommended

The privileged helper image should be pinned, and amd64 emulation guidance is incomplete for arm64 Linux hosts.

Review effort: Balanced
Findings: 1 · 1

Open (2)

• Pin tonistiigi/binfmt image to an immutable reviewed digest · New
• Add arm64 emulation for amd64 builds on arm64 hosts · New

[Copilot]

Copilot review overview

🟢 Approval recommended

The documented commands align with the workflow and Dockerfile requirements.

Review effort: Balanced
Findings: None

Resolved since last review (2)

• Pin tonistiigi/binfmt image to an immutable reviewed digest
• Add arm64 emulation for amd64 builds on arm64 hosts