[FEATURE]: "Compact above" - Partial Compaction #9896
Description
Describe the enhancement you want to request
In a long-running session, you often know exactly which part of the conversation has become less relevant and can be compacted. The same way, you know that e.g. the last 8 messages of the dialog are critical and must be retained verbatim.
What if we added a "Compact above" (or "Compact up to here" or "Compact from here") action to the Message Actions?
(nanobanana mockup)
Loosely related to #4659