Swip 048 - Pushsync forwarding from in-AOR full nodes to closest nodes

[lat-murmeldjur]

Summary

Pushsync should keep a chunk moving toward the closest currently selectable reachable peer. A full node that is inside the chunk's area of responsibility will store the chunk locally, but a local receipt should be a time bounded fallback, not the first result returned upstream.

This SWIP builds on bee#5390, which addresses out-of-depth storing, shallow receipts, and false ChunkSynced reporting. The additional change is limited to forwarder behaviour: an in-AOR full node should not stop the push path while normal forwarding can still progress, and ErrWantSelf should not bypass the overdraft refresh path when temporary accounting skips may soon clear.

[acud]

@lat-murmeldjur can we please have:

• more clear and succinct description of the swip
• remove the protocol suggested changes diff (especially the inline diff which is just not very legible)
• add diagrams as to what this changes - how do things currently behave vs how they would after this change is shipped

thanks