Fix database directory creation at startup

src/content_engine/models/database.py

@@ -2,7 +2,9 @@
 
 from __future__ import annotations
 
+import os
 from datetime import datetime
+from pathlib import Path
 
 from sqlalchemy import (
     Boolean,
@@ -149,6 +151,11 @@ class ScheduledPost(Base):
 
 # --- Engine / Session factories ---
 
+# Ensure database directory exists before creating engine
+_db_path = settings.database.url.replace("sqlite+aiosqlite:///", "")
+_db_dir = Path(_db_path).parent
+_db_dir.mkdir(parents=True, exist_ok=True)
+
 _catalog_engine = create_async_engine(
     settings.database.url,
     echo=False,