fix(ci): build the ARM64 app image on a 16 vCPU runner

[waleedlatif1]

Summary

• Move the ARM64 app image build from blacksmith-8vcpu-ubuntu-2404-arm (24 GB) to blacksmith-16vcpu-ubuntu-2404-arm (48 GB), matching the AMD64 app build's 16 vCPU runner
• The app build outgrew the 8 vCPU ARM box: next build was OOM-killed (SIGKILL / ResourceExhausted) while collecting page data with 7 workers at --max-old-space-size=8192, and a rerun died mid-compile with a missing .next manifest (ENOENT). The AMD64 build of the same commit passed
• A failed ARM64 app build skips the GHCR manifests, attestation, and GitHub release, so the release never publishes for self-hosted deployments
• Non-app ARM images and the GitHub-hosted fallback runner are unchanged

Type of Change

• Bug fix

Testing

bun run lint, block registry check, bun run check:audits (49 audits), and docs-manifest:check pass. The ARM64 matrix only runs on push to main, so the new runner is exercised on the next release

Checklist

• Code follows project style guidelines
• Self-reviewed my changes
• Tests added/updated and passing
• No new warnings introduced
• I confirm that I have read and agree to the terms outlined in the Contributor License Agreement (CLA)

🤖 Generated with Claude Code

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Project	Deployment	Actions	Updated
docs	Ready	Preview	Sep 25, 2026 8:28am UTC

[cubic-dev-ai]

No issues found across 1 file

Confidence score: 5/5

• Automated review surfaced no issues in the provided summaries.
• No files require special attention.

_{Re-trigger cubic}

[greptile-apps]

Confidence Score: 5/5

[High risk] Changes the build runner for ARM64 container images.

The PR appears safe to merge based on the reviewed workflow change.

Summary

The PR moves the ARM64 app image build to a 16 vCPU Blacksmith runner to address build-time memory exhaustion. It leaves the other ARM images and GitHub-hosted fallback unchanged.

_{Reviews (1) · Last reviewed commit: "fix(ci): build the ARM64 app image on a ..."}