chore(ci): remove dead Codecov upload steps + lock pins

[hyperpolymath]

Removed CI references to apps that are no longer installed on this account/org.

Why this is a fix, not a tidy-up

• Codecov was uninstalled as a GitHub App, but its action steps remain in workflows.
• The estate Actions allowlist already pruned codecov/codecov-action@* (standards/config/settings/actions-allowlist.json -> pruned_from_live_2026_09_02), so a workflow still calling it fails at job start instead of quietly no-op-ing.
• Snyk / Codacy / Mergify / ImgBot / CodeFactor are on the estate never-re-add list (standards spec §9, rulings R1/R4/R5).

Changes

Notes

• actions.lock entries for the removed actions are deleted in this same commit (the same-PR regen rule in the CI/CD regularisation spec §6.4), so actions-lock-verify sees no drift.
• Removals are line-exact; no other line was reformatted and no comment was re-wrapped.
• Historical records (milestone logs, CHANGELOG, audit docs, specs) that describe the removal were deliberately left untouched.
• The gitar-approved label is intentionally frozen per docs/LABELS.adoc — it is not an active Gitar install, so it stays.

[coderabbitai]

No actionable comments were generated in the recent review. 🎉

ℹ️ Recent review info

⚙️ Run configuration

Configuration used: Organization UI

Review profile: ASSERTIVE

Plan: Advanced

Run ID: 0375b9cb-f1ec-4cba-8e4b-ddaa4b211f9e

📥 Commits

Reviewing files that changed from the base of the PR and between 6ae5650 and 7a84da3.

📒 Files selected for processing (1)

• codecov.yml

💤 Files with no reviewable changes (1)

• codecov.yml

Included review availability: Your plan provides up to 1 included review per hour; 0 remain after this review.

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📝 Summary

Summary by CodeRabbit

• Chores
  • Removed the Codecov configuration, including coverage thresholds, status checks, reporting comments, ignored paths, and language-specific coverage settings.

Walkthrough

The pull request deletes codecov.yml. This removes the configured coverage thresholds, status checks, reporting behaviour, ignored paths, and Rust and Julia coverage flags.

Changes

Codecov configuration

Layer / File(s)	Summary
Remove Codecov settings codecov.yml	The complete Codecov configuration is deleted, including coverage thresholds, reporting options, ignored paths, and Rust and Julia flag settings.

Priority: ⬇️ Low

Estimated code review effort: 1 (Trivial) | ~5 minutes

Change: Other

🚥 Pre-merge checks | ✅ 5

✅ Passed checks (5 passed)

Check name	Status	Explanation
Title check	✅ Passed	The title clearly identifies the main change: removing obsolete Codecov upload steps and related lock pins.
Description check	✅ Passed	The description explains the removal of obsolete CI references, the reason for the fix, and the related lock-file changes.
Docstring Coverage	✅ Passed	No functions found in the changed files to evaluate docstring coverage. Skipping docstring coverage check. Docstring coverage is scoped to functions touched by this diff. Analyzed 0 functions across 0…
Linked Issues check	✅ Passed	Check skipped because no linked issues were found for this pull request.
Out of Scope Changes check	✅ Passed	Check skipped because no linked issues were found for this pull request.

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_{A rabbit finds the coverage file gone
Thresholds and flags no longer dawn
Rust and Julia rest
Reporting is suppressed
The clean repository hops along}

_{Comment @coderabbitai help to get the list of available commands.}