ci(pr): summarize CI status and failures in one comment

[sara4dev]

Summary

Adds one updating PR comment for Pre Merge, PR, and PR-XPU with the current head SHA, emoji status labels, failed steps, bounded sanitized log excerpts, and links to full logs. This gives contributors and agents useful failure evidence without downloading entire CI logs.

The reporter runs trusted default-branch code, handles fork PRs and partial reruns, and rejects stale or ambiguous results. Fern preview updates now target their own comment so they cannot overwrite the CI summary.

Refs DYN-4542. Inspired by the FlashInfer example.

Validation

• 70 dependency-free Node tests passed, covering PR resolution, freshness, reruns, comment identity, bounded downloads, escaping, and redaction.
• Repository pre-commit checks and action-pin validation passed.
• Read-only replay against PR refactor(operator): separate managed Grove components #15311 produced the expected summary of a failed second CI attempt, including the actual pytest failure. Fork fallback resolved PR fix(llm): pin frontend HF resolution to the worker's commit SHA via ModelExpress 0.6.0 #11369 when both GitHub association APIs were empty.
• Live bot smoke test passed: created the real CI summary, replaced an outdated body using the same comment ID, and repeated publication without duplicates.
• A separate CPU job intentionally failed; its labeled failure example verifies real log extraction, credential redaction, HTML escaping, and saved comment content. The fixture is not a failure of this PR's CI, and the temporary harness is outside this PR diff.
• Executed the Fern preview script with mocked APIs: legacy preview updates and separate comment creation both passed.

Draft pending full CI and maintainer review. Live comment publication is verified; automatic workflow_run triggering and event-to-PR resolution still need validation after merge to the default branch. This reports three named workflows and diagnostic excerpts, without nightly comparisons or inferred root-cause labels.

[github-actions]

CI status

PR head: d51d65cd9fac2c139677b94050a8d1b1a8a222f3

Workflow	Status	Jobs	Run
Pre Merge	⏳ Queued	11 total: 2 passed, 0 failed, 3 skipped, 0 cancelled, 5 running, 1 queued	Run 36508654392 · attempt 1
PR	⏳ Pending	0 total: 0 passed, 0 failed, 0 skipped, 0 cancelled	Run 36508657280 · attempt 1
PR-XPU	✅ Pass	4 total: 1 passed, 0 failed, 3 skipped, 0 cancelled	Run 36508656801 · attempt 1

Legend: ✅ Pass · ❌ Failed · ⏱ Timed out · 🔄 Running · ⏳ Pending · 🚫 Cancelled · — Skipped / not run · ⚠️ Needs attention · ➖ Neutral · ❔ Unknown.

Counts include skipped and cancelled jobs; they are not passing tests.

Failure excerpts are selected from job logs and may be incomplete. Open the linked job or run for the full logs.

[github-actions]

Intentional smoke-test fixture, separate from this PR's CI results.

CI status

PR head: d51d65cd9fac2c139677b94050a8d1b1a8a222f3

Workflow	Status	Jobs	Run
Intentional CPU fixture (smoke test only)	🔄 Running	1 total: 0 passed, 1 failed, 0 skipped, 0 cancelled	Run 36508692051 · attempt 1

Legend: ✅ Pass · ❌ Failed · ⏱ Timed out · 🔄 Running · ⏳ Pending · 🚫 Cancelled · — Skipped / not run · ⚠️ Needs attention · ➖ Neutral · ❔ Unknown.

Counts include skipped and cancelled jobs; they are not passing tests.

Intentional CPU fixture (smoke test only) failures

Intentional CPU failure fixture — ❌ Failed

Open job log

Failed steps:

• Emit an intentional diagnostic (❌ Failed)

Complete job name: Intentional CPU failure fixture
##[group]Run echo 'FAILED ci_summary_smoke::intentional_failure - AssertionError: expected smoke-test failure'
echo 'FAILED ci_summary_smoke::intentional_failure - AssertionError: expected smoke-test failure'
echo 'FAILED ci_summary_smoke::escaping - AssertionError: <tag> must be escaped; token=[REDACTED]
exit 1
##[endgroup]
FAILED ci_summary_smoke::intentional_failure - AssertionError: expected smoke-test failure
FAILED ci_summary_smoke::escaping - AssertionError: <tag> must be escaped; token=[REDACTED]
##[error]Process completed with exit code 1.

Failure excerpts are selected from job logs and may be incomplete. Open the linked job or run for the full logs.

[github-actions]

🌿 Fern Docs Preview: https://nvidia-preview-01a0ead3-4f62-75d7-a9a9-b658e3121a87.docs.buildwithfern.com/dynamo/dev