Enable writing of intermediate nodes#135

Draft

kmchicoine wants to merge 4 commits intomainfrom

kaley/intermediate-node

Commits on Jun 6, 2025

build in memory trie
kmchicoine
committed

Commits on Jun 9, 2025

tests for in memory trie building
kmchicoine
committed

Commits on Jun 10, 2025

merge in memory subtrie with on disk subtrie
kmchicoine
committed

Commits on Jun 11, 2025

comment cleanup
kmchicoine
committed