[desrosj]

The ubuntu-26.04 runner image is now generally available, and ubuntu-latest is moving from 24.04 to 26.04 between 2026-10-19 and 2026-11-19 (tracked in actions/runner-images#14748).

This PR updates every workflow and reusable workflow that currently pins ubuntu-24.04 to use ubuntu-26.04 instead (43 files, including the default os input on the reusable workflows).

Also:

• The pinned actionlint version (v1.7.11) does not recognize the ubuntu-26.04 label yet, so it is temporarily registered in .github/actionlint.yaml.
• Updated the comment above the AppArmor workaround in reusable-javascript-tests.yml so it no longer refers only to 24.04.

Note: the versioned reusable workflows (-v1, -v2, and so on) are also called from older branches. Changing their default os input will move those branches to 26.04 too, unless they pass os explicitly.

This is a draft while the workflow results are reviewed.

Trac ticket: Core-66499

Use of AI Tools

Claude Code (Claude Opus 5.5) made the label replacement and the actionlint config change, and drafted this description. Draft PRs should be considered unverified and unreviewed by a human.

🤖 Generated with Claude Code

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[lancewillett]

Reviewed at e7eef8e. This looks good to me.

• All 80 ubuntu-24.04 pins on trunk are swapped, including the reusable os defaults and matrix includes. The macOS and Windows runners are correctly left alone.
• The actionlint entry is still needed: actionlint's main branch doesn't know ubuntu-26.04 yet.
• CI is green on the 26.04 image: 618 passed, 0 failed.

Two notes for landing:

1. The PR ran the limited PHPUnit matrix. Adding the "Full PHPUnit Matrix" label would cover the scheduled set once before commit.
2. Older branches call the v1/v2/v3 and other reusables at trunk without passing os, so they move to 26.04 with this commit. That path, including the AppArmor step for branches before 6.1, only gets tested by the "Test old branches" run the commit triggers. Worth watching.

Also, the description still says it's a draft.

_{AI review · claude-opus-5-5}