Release Devnet4 v0.4.27

[zclawz]

Release PR for Devnet4 v0.4.27, following RELEASE.md.

Expected workflow outputs after merge:

• Git tags: v0.4.27, Devnet4
• Docker images: blockblaz/zeam:0.4.27, blockblaz/zeam:devnet4, and arch-specific tags/manifests
• Branch update: devnet4
• GitHub prerelease: Zeam Devnet4 Release

[ch4r10t33r]

LGTM

[zclawz]

CI Failure Analysis — test (macos-latest) ❌

Failed test: SSE events integration test - wait for justification and finalization
File: pkgs/cli/test/integration.zig:789

What happened

The simtest ran for the full 480s timeout and never reached got_node3_sync:

STATUS: got_justification=true got_finalization=true got_node3_sync=false
FAIL (TestUnexpectedResult)
try std.testing.expect(got_node3_sync);

Justification ✅ and finalization ✅ both succeeded — only the node3 sync check timed out. The CI runner retried 3×, all failed the same way.

Ubuntu passed ✅ — this is macOS-only, suggesting a timing/performance issue on the aarch64 macOS runner rather than a code regression.

Likely cause

Flaky simtest: node3 sync is slow on the macOS GitHub Actions runner (aarch64). The 480s timeout is tight enough that occasional runner congestion or latency spikes tip it over. Not a code bug in the release branch.

Recommendation

Re-run the macOS test job. If it passes on re-run, this is confirmed flaky and the release can proceed. If it consistently fails, the sync logic for node3 may need investigation.