Entity pickers and refresh

Goal#

Fill a channel, category, or role field with the real thing, not a pasted id.

Steps#

1. Any field that takes channels, categories, or roles opens a searchable picker listing your server's actual entries. Type to narrow, click to pick, picked entries float to the top.
2. The list comes from a snapshot the bot keeps current as your server changes.
3. Just created a channel or role and it is not in the list? Press the refresh button next to the picker. The bot updates the snapshot and the list catches up in a moment.
4. A picked entry that is later deleted on Discord does not break the rule: the missing reference is simply skipped in evaluation.