fix: update test fixtures for SQLite storage migration

All store tests were passing file paths instead of Database objects
after the JSON-to-SQLite migration. Updated fixtures to create temp
Database instances, rewrote backup e2e tests for binary .db format,
and fixed config tests for the simplified StorageConfig.

server/tests/test_device_store.py

@@ -2,19 +2,22 @@
 
 import pytest
 
+from wled_controller.storage.database import Database
 from wled_controller.storage.device_store import Device, DeviceStore
 
 
 @pytest.fixture
-def temp_storage(tmp_path):
-    """Provide temporary storage file."""
-    return tmp_path / "devices.json"
+def tmp_db(tmp_path):
+    """Provide a temporary SQLite Database instance."""
+    db = Database(tmp_path / "test.db")
+    yield db
+    db.close()
 
 
 @pytest.fixture
-def device_store(temp_storage):
+def device_store(tmp_db):
     """Provide device store instance."""
-    return DeviceStore(temp_storage)
+    return DeviceStore(tmp_db)
 
 
 def test_device_creation():
@@ -207,10 +210,11 @@ def test_device_exists(device_store):
     assert device_store.device_exists("nonexistent") is False
 
 
-def test_persistence(temp_storage):
+def test_persistence(tmp_path):
     """Test device persistence across store instances."""
+    db = Database(tmp_path / "persist.db")
     # Create store and add device
-    store1 = DeviceStore(temp_storage)
+    store1 = DeviceStore(db)
     device = store1.create_device(
         name="Test WLED",
         url="http://192.168.1.100",
@@ -218,14 +222,15 @@ def test_persistence(temp_storage):
     )
     device_id = device.id
 
-    # Create new store instance (loads from file)
-    store2 = DeviceStore(temp_storage)
+    # Create new store instance (loads from database)
+    store2 = DeviceStore(db)
 
     # Verify device persisted
     loaded_device = store2.get_device(device_id)
     assert loaded_device is not None
     assert loaded_device.name == "Test WLED"
     assert loaded_device.led_count == 150
+    db.close()
 
 
 def test_clear(device_store):