chore: bump checkout->v5, setup-python->v6 (Node 24 native)

[ErikBjare]

Follow-up to the v2->v4 / v1->v5 bump: v4/v5 still target Node 20 and get force-run on Node 24 with a deprecation warning. v5/v6 are Node-24-native and clear it. (The remaining Node-20 warning is from JamesIves/github-pages-deploy-action@4.1.8, out of scope here.)

[greptile-apps]

Greptile Summary

This PR updates the Pages workflow actions to their Node 24 native versions.

• actions/checkout moves from v4 to v5.
• actions/setup-python moves from v5 to v6.
• The existing checkout and Python inputs stay unchanged.

Confidence Score: 5/5

This looks safe to merge.

• No blocking issues found in the changed code.
• The updated actions keep the same inputs used by this workflow.
• The workflow runs on ubuntu-latest, which matches the intended runtime for these action versions.

Important Files Changed

Filename	Overview
.github/workflows/pages.yml	Bumps the checkout and setup-python workflow actions while keeping the existing inputs and job flow unchanged.

_{Reviews (1): Last reviewed commit: "chore: bump checkout->v5 and setup-pytho..." | Re-trigger Greptile}