v2.0.25

fix(ha): move DwmStore JSON I/O off the event loop

HA's loop watchdog flagged blocking open() in store.py:
- _load called sync from __init__, hit during async_setup_entry
- _save called from every _set, hits ~1Hz from heartbeat loop

Refactor:
- async_create() factory dispatches initial read to executor
- _save deepcopies and schedules executor write (fire-and-forget)
- _sync_load/_sync_save are executor-only sync primitives

Update __init__.py to await DwmStore.async_create().