ci: use node24 fork of setup-zig

[drawmeanelephant]

Agent Completion Report

• Status: complete
• Branch and Worktree:
  • Branch: ci/fork-setup-zig-node24
  • Worktree: ci/fork-setup-zig-node24 (main checkout)
• Commit and PR:
  • Commit: ad3b8dc1
  • Target PR / Branch: ci: use node24 fork of setup-zig #964 / main
• Linked Issues (auto-close convention):
  • None. CI maintenance follow-up to ci(pages): bump Pages actions off deprecated Node 20 #962 and ci: bump CI actions off deprecated Node 20 and pin by SHA #963.
• Changed Files:
  • .github/workflows/ci.yml
  • .github/workflows/github-pages.yml
  • docs/changelog.d/964-fork-setup-zig-node24.md
• Preserved Unrelated Files:
  • No other tracked files modified; branch from an up-to-date main with a clean tree.
• Implementation Summary:
  • Created drawmeanelephant/setup-zig, a fork of mlugg/setup-zig at v2.2.1 (commit d1434d0), changing only action.yml runs.using: node20 → node24 plus a README provenance note; pushed commit 0ebfa31d and tag v2.2.1-node24.
  • Repointed all nine setup-zig uses across ci.yml and github-pages.yml to the fork, pinned by commit SHA.
  • Added the required changelog fragment.
• Known Gaps:
  • The fork is user-owned; functional upstream updates must be pulled manually. No functional divergence at this time.
• Exact Commands Run:
  1. gh api -X POST repos/mlugg/setup-zig/forks
  2. gh repo clone drawmeanelephant/setup-zig (temp workspace)
  3. git push origin main --tags
  4. zig build test
  5. gh pr checks 964 (pending at report time)
• Exact Gate Results:
  • zig build test: pass
  • ci.yml / github-pages.yml YAML parse: pass
  • No mlugg/setup-zig references remain: verified
  • Repo actions policy allowed_actions: all: verified
  • PR CI (all lanes, fork action load): running
• Determinism Result:
  • N/A — workflow pin change only.
• Generated Artifacts:
  • None in the Boris repo. Fork commit/tag live at drawmeanelephant/setup-zig.
• Blockers and Next Card:
  • Blockers: None
  • Next Card: Confirm all ci lanes pass with the fork action and no Node 20 annotation remains, then merge.