StateStoreModule

Persists the module configuration + per-control values across reboots. On boot, reads /modules.json (LittleFS) and re-instantiates each listed module, then per-module /state-<id>.json applies the saved control values via setControl. Every 10 s, snapshots the current state and writes any diff. Sits at module slot 5 in main.cpp (after the four head modules) so its setup can mm.add() user-added modules before any other module's first loop tick. See Sprint 6 for the design discussion.

End-user reference

No user-facing controls beyond enabled. Side effects on disk:

File	Written when	Contents
/modules.json	Module list changes (add / remove / reorder)	[{type, id}, …]
/state-<id>.json	Any control value on <id> changes	{control_key: value, …} per module

Both files are gitignored on PC (PalFs PC root is ./state/).

Developer reference

• setup() — read /modules.json and per-module /state-<id>.json; for each entry, call manager_->add(type, id) and apply saved control values via setControl(). Seed the dirty-detection cache with the in-memory snapshot (so the first loop10s tick doesn't immediately re-write what was just loaded).
• loop10s() — snapshot the current module list + per-module state, diff against last snapshot, write changed entries to disk. Removed-module state files stay on disk (PalFs fs_unlink is deferred — see backlog).