fix(db): use settings for connection to support native env

app/deps.py

@@ -8,11 +8,12 @@ from config import get_settings
 
 def get_db():
     # Einfache, robuste DB-Verbindung pro Aufruf
+    settings = get_settings()
     conn = pymysql.connect(
-        host=os.getenv("MARIADB_HOST", "db"),
-        user=os.getenv("MARIADB_USER", "crumb"),
-        password=os.getenv("MARIADB_PASSWORD", "secret"),
-        database=os.getenv("MARIADB_DATABASE", "crumbcrm"),
+        host=settings.mariadb_host,
+        user=settings.mariadb_user,
+        password=settings.mariadb_password,
+        database=settings.mariadb_database,
         autocommit=True,
         charset="utf8mb4",
         cursorclass=DictCursor,