feat: pruned nodes #6953
Description
Mainnet storage is at ~1TB, dominated by historical MARF data (~95%) and keeps growing at a rate of ~2.73GB/day.
If the at-block removed will be accepted, it would open the path to pruned nodes based on MARF squashing.
This issue tracks the implementation of snapshot/pruned nodes that:
- squash MARF state at snapshot height H (drop historical trie nodes),
- preserve full block data (so nodes can still serve genesis-syncing peers),
- keep consensus root-hash behavior correct above H,
- support proof generation/verification on squashed state (including squash-shunt flow and trusted squash root hashes).