Abandons the HMAC-keyed PDS-record storage scheme (putRecord/deleteRecord/ listRecords never shipped upstream) in favor of the private, per-account synced settings API. Drops the multi-key/secret UI, which only existed to let a shared secret be pasted into another device/app to derive the same public record — meaningless now that storage is private and auto-synced. Also uses Modal.update() so removing a tag while browsing a tag list refreshes the modal in place instead of closing and reopening it.