internal/

Package candidatecache holds the per-replica bounded set of step candidates produced by the engine's refiller.

Package database owns the engine's sharded SQL connections: it opens and migrates every shard, routes by 1-based shard index, fans an operation out over all shards, and closes them.

Package keys encodes and decodes the engine's composite flow and step keys.

Package lru provides a small thread-safe LRU cache with a per-entry TTL.