catch-up mode

[Aethelraed]

A transient mode listing all unread emails regardless of position in folders.
Get an overview over all unread emails and easy access to common actions like move, reply, mark as spam, archive, rule creation, filter, search, forward...

Motivation:

automatic empty inbox, without having to locate each unread email inside a nested folder structure

Alternatives:

• Ability to add event-listeners to inbox rules — move / burn after reading
• Filter to single out all unread email — :unread flag inside search
• Ephemeral automatic self-deleting copies of (pointer)emails upon receipt into the inbox folder

Nice to have

• tags / labels
• priority
• automatic sort inside transient view by priority / recency / length / tags

In a sense it is like a global version of Filter for unread emails #5431