Extract the storage layer into core

core/store.py

@@ -0,0 +1,30 @@
+"""SQLite storage path resolution for the NestQuest storage layer.
+
+Home-Assistant-free: callers resolve the database file location from
+their own config (HA resolves it from ``hass.config.path``) and pass
+the full path here; this module ensures the parent directory exists
+off-thread via :func:`asyncio.to_thread` and returns the absolute path.
+"""
+from __future__ import annotations
+
+import asyncio
+from pathlib import Path
+
+
+def _ensure_dir(path: Path) -> None:
+    """Create the given directory and any missing parents."""
+    path.mkdir(parents=True, exist_ok=True)
+
+
+async def async_get_db_path(db_path: Path | str) -> Path:
+    """Return the absolute path to the NestQuest SQLite database file.
+
+    ``db_path`` is the full path to the database file (the integration
+    resolves it from ``hass.config.path(SQLITE_DB_FILENAME)``); the
+    parent directory is created off the event loop via
+    :func:`asyncio.to_thread` so this module never blocks and never
+    imports Home Assistant.
+    """
+    path = Path(db_path).absolute()
+    await asyncio.to_thread(_ensure_dir, path.parent)
+    return path