ci: make Codecov reporting informational

[zoeyrose]

Summary

Codecov coverage percentages and external upload/report availability no longer block the required Classic validation check.

Implementation / behavior

• Configure Codecov project and patch status checks as informational.
• Keep all five OIDC coverage uploads, but bound each to two minutes and continue the workflow if Codecov setup or upload fails.
• Remove the 15-minute Codecov API polling gate.
• Preserve native coverage generation, GPU coverage validation, coverage artifacts, and the strict Classic validation aggregate.
• Classify codecov.yml as shared native validation input, so future config-only changes still select client and server coverage lanes.

Validation

• python3 -m unittest tools.tests.test_classify_changes tools.tests.test_workflow_contracts — 68 tests passed.
• python3 tools/verify_import_history.py — passed.
• git diff origin/main...HEAD --check — passed.
• Independent review approved the exact refreshed diff.
• On head 571a6570b677f3e534ec8fd507ab508c1b1c2774, PR benchmarks passed; Classic Check and CodeQL were still running with no failures observed at last check.
• Local actionlint is unavailable; hosted workflow checks remain in progress.

Limitations / follow-up

Codecov statuses may still appear as informational checks when Codecov processes reports. They are not required by the active Classic ruleset. This PR remains unmerged for maintainer review.

[chatgpt-codex-connector]

Codex Review Summary

This comment shows the latest Codex review activity on this pull request.

Review	Status	Commit	Review trigger
📝 Code Review	✅ Completed 2026-10-06T01:27:41.939524Z	d1b9288	PR opened
🔒 Security Review	✅ Completed 2026-10-06T01:28:01.165362Z	d1b9288	PR opened

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review" or "@codex security review".

Codex reacts with 👀 while any review is running, comments if it has suggestions, and reacts with 👍 once all reviews finish with no findings.

[chatgpt-codex-connector]

💡 Codex Review

Here are some automated review suggestions for this pull request.

Reviewed commit: d1b9288ddf

ℹ️ About Codex in GitHub

Your team has set up Codex to review pull requests in this repo. Reviews are triggered when you

• Open a pull request for review
• Mark a draft as ready
• Comment "@codex review".

If Codex has suggestions, it will comment; otherwise it will react with 👍.

Codex can also answer questions or update the PR. Try commenting "@codex address that feedback".

[codecov]

Codecov Report

✅ All modified and coverable lines are covered by tests.

📢 Thoughts on this report? Let us know!