Module store 

RuntimeThreadStore — persisted JSON state (issue #5261 / #3313).

The store is the state.json + <root>/{threads,turns,items,events} layout that crates/state already owns. This module is the core owner for that layout so the TUI’s RuntimeThreadManager can be split without changing the file shape. The current ThreadManager in crates/core/src/lib.rs already uses StateStore; this file is the next home for that impl once the git mv lands. Until then it documents the contract and exposes the typed store handle.

Structs

ThreadStore

Typed handle over StateStore that the executor and events modules share. The methods are thin wrappers so the store boundary is greppable and the persisted shape can be asserted in one place (back-compat tests hold).