Explicitly notify Codecov about upload completion

[webknjaz]

This patch add an additional invocation of Codecov CLI that tells the backend that we're done uploading. It is supposed to stop Codecov from guessing whether to wait for more uploads for the CI or start processing them already.

Upstream refs:

• https://docs.codecov.com/docs/cli-options#send-notifications
• https://docs.codecov.com/docs/notifications#preventing-notifications-until-youre-ready-to-send-notifications
• https://docs.codecov.com/docs/codecovyml-reference#codecovnotifymanual_trigger
• Complete upload command codecov/codecov-cli#195 (getsentry/prevent-cli@d634ebd)
• Add support for send-notifications in codecov-action codecov/codecov-action#1436
• Manual Trigger for Commit Report Upload Completion codecov/engineering-team#107
• Manual trigger for commit report upload completion codecov/roadmap#20
• Move `after_n_builds` earlier in the report processing cycle. codecov/feedback#204 (comment)
• Move after_n_builds earlier in the report processing cycle. codecov/engineering-team#1245
• Integrate the Manual Trigger with Codecov CLI codecov/engineering-team#3
• manual trigger codecov/worker#14 (codecov/umbrella@71626b6)

What do these changes do?

SSIA.

Are there changes in behavior for the user?

Nope.

Related issue number

N/A

Checklist

• I think the code is well written
• Unit tests for the changes exist
• Documentation reflects the changes

[Copilot]

Pull Request Overview

This PR configures the CI pipeline to explicitly notify Codecov when all coverage uploads are complete, eliminating the need for Codecov to guess when processing should begin.

• Adds a new coverage-summary job that sends completion notifications to Codecov
• Updates Codecov configuration to use manual trigger mode instead of counting builds
• Adds actionlint configuration to ignore a known issue with the codecov action

Reviewed Changes

Copilot reviewed 4 out of 4 changed files in this pull request and generated no comments.

File	Description
CHANGES/1577.packaging.rst	Documents the CI enhancement for Codecov notification
.github/workflows/ci-cd.yml	Adds coverage-summary job to notify Codecov of upload completion
.github/actionlint.yml	Configures actionlint to ignore codecov action input validation
.codecov.yml	Switches from build counting to manual trigger mode

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[codspeed-hq]

CodSpeed Performance Report

Merging #1577 will not alter performance

_{Comparing webknjaz:maintenance/codecov-send-notifications (00ec6a0) with master (c3d4570)}

Summary

✅ 101 untouched

[Dreamsorcerer]

Should it work within this PR? Seems there's no notification..

[webknjaz]

I imagine Codecov might be waiting to process the reports before posting. Let's observe in the near future.. Also, check statuses also count as notifications, I think.

[Dreamsorcerer]

Pretty sure it's already finished, I can't see any signs that it's processing still. Usually only takes a few seconds anyway.

[webknjaz]

Maybe I should've kept wait_for_ci: false..