Module session 

Session glues the pieces: it owns the append-only log and the folded state, routes commands through step, and notifies observers. Save/load is literally serialize/replay the log — there is no separate save-game format to drift out of sync.

Structs

Session

Functions

load_log

save_log

JSON-lines event log persistence: one event per line, append-friendly, diffable, trivially inspectable. (SQLite — the settled storage choice — arrives when there is queryable state worth indexing, Phase 2 stats; see the delivery notes.)