chore(node): bump to 24.21.0

[web-enablement-automation]

Bumping Node to 24.21.0

Active LTS is now 24.21.0. This repo's mise config was pinned to 18.20.5, so nodysseus opened this PR to bring it up to date.

What changed

• mise use node@24.21.0 was run at the repo root, which:
  • Updated the pinned node version in:
    - mise.toml (18.20.5 → 24.21.0)
  • Refreshed mise.lock to match.

Reviewer checklist

• CI is green.
• Local pnpm install (or your equivalent) still works under the new node version.
• No unexpected changes outside mise.toml / mise.lock.

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Opened by nodysseus. Questions? Ping #web-enablement.

[stepsecurity-app]

Security Policy Alert: Actions Policy Violation

This workflow run has been blocked by StepSecurity's actions policy.

Actions Not Pinned to SHA:

• jdx/mise-action@v4

To fix this issue, please pin each action to a full 40-character commit SHA instead of a tag or branch reference.

For more information, see StepSecurity's Actions Policy documentation.