AI helped me put these questions together, so if you need me to clarify, please let me know!

We track judges on our event CPT using three text fields (judge-one, judge-two, judge-three) and need to support more than three. Plan: replace them with a repeater field and migrate existing data in. Doing this mostly via CLI.

1. We’ve confirmed via wp-cli that the repeater stores as a JSON-encoded array of {key: value} objects in a single postmeta field — is this the stable, documented format, or subject to change?

2. Is there a supported way to write to a repeater field programmatically (WP-CLI command, action/filter hook, PHP function) rather than a raw SQL UPDATE to postmeta?

3. Does “Index all posts” fully rebuild the index table from postmeta for every post, or only process posts changed since the last run? We’re bulk-migrating 1,727 posts outside the normal save/edit UI and need to know if the index table picks that up automatically or needs to be told.

4. Is there a recommended approach or tooling for bulk-migrating data from one field structure to another (e.g., text fields to a repeater)?