ci: temporarily disable focal job in merge-queue and nightly flows

[dor-forer]

Describe the changes in the pull request

Comment out the focal job (and its corresponding needs: entry) in both event-merge-to-queue.yml and event-nightly.yml, so the merge queue and nightly notifier are no longer blocked by Ubuntu 20.04 CI failures.

For the past several days, Canonical's PPA edge (ppa.launchpad.net / ppa.launchpadcontent.net, both resolving to 185.125.190.80) has been intermittently refusing connections, causing add-apt-repository ppa:ubuntu-toolchain-r/test to fail in .install/ubuntu_20.04.sh. We need that PPA because focal's stock GCC is 9, but the SVS code path requires C++20 features that need GCC ≥ 11 (see cmake/svs.cmake). The outage was verified from both the GitHub-hosted runner and a local network, confirming it is upstream and not workflow- or runner-related; no amount of apt retry/timeout/mirror-swap configuration in our workflow can route around it.

focal.yml itself is left untouched and remains manually-triggerable via workflow_dispatch, so we can keep iterating on a fix (likely a pre-built CI image with gcc-11 baked in to remove the per-run Launchpad dependency) without re-enabling it in any auto-flow. A TODO: comment marks the spot for re-enablement.

Which issues this PR fixes

1. N/A — unblocks the merge queue from a transient upstream (Canonical) outage; no internal issue ID.

Main objects this PR modified

1. .github/workflows/event-merge-to-queue.yml — focal job and its entry in pr-validation.needs commented out.
2. .github/workflows/event-nightly.yml — focal job and its entry in notify-on-failure.needs commented out.

Mark if applicable

• This PR introduces API changes
• This PR introduces serialization changes

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Note

Low Risk
Low risk: workflow-only change that removes Ubuntu 20.04 (focal) from required job dependencies, which may reduce CI coverage but does not affect runtime code.

Overview
Temporarily comments out the Ubuntu 20.04 (focal) job in event-merge-to-queue.yml and event-nightly.yml, with a TODO note for re-enabling.

Updates the aggregate gating jobs (pr-validation and notify-on-failure) to drop focal from their needs, so merge-queue validation and nightly notifications no longer wait on focal results.

^{Reviewed by Cursor Bugbot for commit 005d600. Bugbot is set up for automated code reviews on this repo. Configure here.}

[jit-ci]

🛡️ Jit Security Scan Results

✅ No security findings were detected in this PR

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^{Security scan by Jit}

[Copilot]

Pull request overview

This PR temporarily removes the Ubuntu 20.04 (“focal”) CI job from the merge-queue and nightly workflows so those automated flows aren’t blocked by upstream Launchpad PPA connectivity failures, while keeping focal.yml available for manual runs.

Changes:

• Commented out the focal job in the merge-queue workflow.
• Commented out the focal job in the nightly workflow.
• Removed focal from the corresponding needs: lists so validation/notification jobs no longer wait on it.

Reviewed changes

Copilot reviewed 2 out of 2 changed files in this pull request and generated 3 comments.

File	Description
.github/workflows/event-nightly.yml	Disables focal in nightly and removes it from notify-on-failure.needs.
.github/workflows/event-merge-to-queue.yml	Disables focal in merge-queue and removes it from pr-validation.needs.

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[github-actions]

Backport failed for 0.6, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin 0.6
git worktree add -d .worktree/backport-954-to-0.6 origin/0.6
cd .worktree/backport-954-to-0.6
git switch --create backport-954-to-0.6
git cherry-pick -x fe175897c1dff9e9f5adb41b030baa34993bcce9

[github-actions]

Backport failed for 0.7, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin 0.7
git worktree add -d .worktree/backport-954-to-0.7 origin/0.7
cd .worktree/backport-954-to-0.7
git switch --create backport-954-to-0.7
git cherry-pick -x fe175897c1dff9e9f5adb41b030baa34993bcce9

[github-actions]

Backport failed for 0.8, because it was unable to cherry-pick the commit(s).

Please cherry-pick the changes locally and resolve any conflicts.

git fetch origin 0.8
git worktree add -d .worktree/backport-954-to-0.8 origin/0.8
cd .worktree/backport-954-to-0.8
git switch --create backport-954-to-0.8
git cherry-pick -x fe175897c1dff9e9f5adb41b030baa34993bcce9

[github-actions]

Git push to origin failed for 8.2 with exitcode 1

[github-actions]

Git push to origin failed for 8.4 with exitcode 1