chore(ci): migrate workflows to Depot runners

[WH-2099]

Background

The existing GitHub Actions workflows still run on ubuntu-latest. Moving them to the repository Depot runner label keeps CI, CLA, test, and release automation on the same runner pool.

Scope

• Update CLA, PR validation/check, release, and test workflow jobs from ubuntu-latest to depot-ubuntu-24.04.
• Keep workflow triggers, permissions, matrices, and action versions unchanged.
• Track PR chore(ci): migrate runners to depot #103 as the implementation for this workflow-only change.

Acceptance Criteria

• The affected GitHub Actions jobs use depot-ubuntu-24.04.
• The linked pull request follows the repository PR template and references this issue.
• No application, packaging, or dependency behavior changes are introduced.