Add LandonSchropp/hunk-review and hunk-backup to the extension directory

[LandonSchropp]

Summary

Adds two hunk-extension-tagged repositories to the community extension directory, inserted alphabetically into EXTENSION_CATALOG in website/src/data/extensions.ts:

• LandonSchropp/hunk-review: Approve or deny the changes from a modal inside Hunk, and stream each decision to an agent or script with hunk review listen.
• LandonSchropp/hunk-backup: Saves every review's comments as they're written, so closing Hunk never loses them, with hunk backup list and hunk backup show to get them back.

version and apiVersion come from each repository's package.json. Both are tagged (v0.2.0 and v0.1.0). The changeset is empty because this only changes website content.

Test plan

• Reviewer to confirm the two listings render on the /extensions/ page in a website build.

[vercel]

@LandonSchropp is attempting to deploy a commit to the Modem Team on Vercel.

A member of the Team first needs to authorize it.

[greptile-apps]

PR author is not in the allowed authors list.