PCD metadata interface

[ichub]

so that cards can have display information associated with them that isn't stored in the PCD itself. For example, it would be good if the user could rename the PCD to whatever name they wanted.

[ichub]

what fields could a PCD metadata object have?

off the top of my head:

• created by <user, website, app>
• created timestamp
• display name
• folder?

cc @gubsheep @rrrliu @robknight @cedoor @artwyman @saurfang

[robknight]

Some speculative ideas:

• Which feed it came from? With the caveat that the user might since have unsubscribed from the feed, so feed details might not be available from subscriptions in e2ee/local storage.

• Priority or "pin to top" so that a PCD can be made to appear higher or lower within a folder (not sure if anyone wants this).

• "Updated timestamp" might also be useful for feed-updated PCDs. In fact, "created timestamp" might be tricky for feed-issued PCDs right now, because we make heavy use of the "replace" action to clear out PCDs in a folder before replacing them with (most of the time) identical ones, but would this reset the created timestamp? If it shouldn't, we might need to adjust how we do this.

• Usage history, showing the times the PCD has been used in the proving screens or as a feed credential.

[cedoor]

It could be nice to know the PCD's version too imo.