[Astro-Han]

Summary

Source qualification runs the Runtime Host suite alongside two other workspaces. At 0b9204b1f, two complete attempts failed differently: the owned-Host startup test missed its 6-second election window, then the event-wait suite stalled until the 15-minute workspace limit. Normal CI runs Runtime Host separately and passed at that commit; both affected files also pass in isolation locally (11 and 251 tests).

Use the existing workspace scheduler override, npm test -- --concurrency=1, in the source-candidate workflow. Each workspace retains its own test-file concurrency. All workspaces, assertions, startup deadlines, and the workspace timeout remain unchanged. This removes cross-workspace resource contention during qualification without changing product code. The full extracted-source workflow must still pass after merge; the isolated checks alone do not qualify an RC or prove every timing issue resolved.

Also record the Composer selector change from #6158, which landed on main while the 0.2.2 qualification was running.

Refs #6148, #6159.

Failed qualification attempts: https://github.com/apache/maka/actions/runs/39200805088

Verification

• 52 workspace scheduler and CI workflow-policy tests passed.
• Verified the actual root test command plus the override parses to concurrency 1 and retains every workspace.
• Workflow YAML parses successfully.
• npm run format, npm run lint, and git diff --check passed.
• On the unchanged source commit, the owned-candidate file passed all 11 tests and event-wait-manager passed all 251 tests locally. No local full-repository suite or E2E was run.
• Full extracted-source qualification remains pending merge.

AI use

• No generative tool made a substantive contribution
• Generative tooling made a substantive contribution

Tool(s) and scope: Codex investigated the two qualification failures, updated the workflow and release note, and ran the targeted checks.

Checklist

• Tests cover the change and fail without it
• Lint, format, typecheck and the affected suites pass locally

Does this PR entail a change in behavior?

• Yes — source qualification runs workspaces one at a time
• No