WA-CI-011: Improve Rails compatibility CI job messaging for expected experimental failures

[kitcommerce]

Summary

The rails_compatibility CI job intentionally allows experimental gemfiles to fail bundler. But when bundler resolution is broken for known reasons (e.g. Mongoid/Rails constraints), it’s helpful to make that explicit and reduce noise.

Objective

Improve the rails_compatibility job ergonomics so contributors quickly understand whether failures are expected vs regressions.

Acceptance Criteria

• In .github/workflows/ci.yml, for experimental matrix entries:
  • Print a clear message when bundle install fails (expected experimental failure), including a link to the tracking issue if known
  • Keep the job continue-on-error behavior unchanged
• Add/update a short doc note describing how to interpret the rails compatibility job output

Verification Plan

• Confirm the workflow logs show the new message when bundle install fails
• Confirm non-experimental entries still fail the workflow when broken

Client Impact

None (CI clarity).

[kitcommerce]

Dispatcher: starting work on this now (automated run). I’ll open a PR targeting next once ready.

[kitcommerce]

Opened PR #866 to improve Rails compatibility CI messaging for expected experimental bundle failures: #866