feat: asset-based image/video sources, notification sounds, UI improvements

- Replace URL-based image_source/url fields with image_asset_id/video_asset_id
  on StaticImagePictureSource and VideoCaptureSource (clean break, no migration)
- Resolve asset IDs to file paths at runtime via AssetStore.get_file_path()
- Add EntitySelect asset pickers for image/video in stream editor modal
- Add notification sound configuration (global sound + per-app overrides)
- Unify per-app color and sound overrides into single "Per-App Overrides" section
- Persist notification history between server restarts
- Add asset management system (upload, edit, delete, soft-delete)
- Replace emoji buttons with SVG icons throughout UI
- Various backend improvements: SQLite stores, auth, backup, MQTT, webhooks

server/tests/e2e/conftest.py

@@ -1,18 +1,47 @@
 """Shared fixtures for end-to-end API tests.
 
-Uses the real FastAPI app with a module-scoped TestClient to avoid
-repeated lifespan startup/shutdown issues. Each test function gets
-fresh, empty stores via the _clear_stores helper.
+Uses the real FastAPI app with a session-scoped TestClient.
+All e2e tests run against an ISOLATED temporary database and assets
+directory — never the production data.
 """
 
+import shutil
+import tempfile
+from pathlib import Path
+
 import pytest
 
-from wled_controller.config import get_config
+# ---------------------------------------------------------------------------
+# Isolate e2e tests from production data.
+#
+# We must set the config singleton BEFORE wled_controller.main is imported,
+# because main.py reads get_config() at module level to create the DB and
+# all stores.  By forcing the singleton here we guarantee the app opens a
+# throwaway SQLite file in a temp directory.
+# ---------------------------------------------------------------------------
 
+_e2e_tmp = Path(tempfile.mkdtemp(prefix="wled_e2e_"))
+_test_db_path = str(_e2e_tmp / "test_ledgrab.db")
+_test_assets_dir = str(_e2e_tmp / "test_assets")
 
-# Resolve the API key from the real config (same key used in production tests)
-_config = get_config()
-API_KEY = next(iter(_config.auth.api_keys.values()), "")
+import wled_controller.config as _config_mod  # noqa: E402
+
+# Build a Config that mirrors production settings but with isolated paths.
+_original_config = _config_mod.Config.load()
+_test_config = _original_config.model_copy(
+    update={
+        "storage": _config_mod.StorageConfig(database_file=_test_db_path),
+        "assets": _config_mod.AssetsConfig(
+            assets_dir=_test_assets_dir,
+            max_file_size_mb=_original_config.assets.max_file_size_mb,
+        ),
+    },
+)
+# Install as the global singleton so all subsequent get_config() calls
+# (including main.py module-level code) use isolated paths.
+_config_mod.config = _test_config
+
+API_KEY = next(iter(_test_config.auth.api_keys.values()), "")
 AUTH_HEADERS = {"Authorization": f"Bearer {API_KEY}"}
 
 
@@ -22,7 +51,7 @@ def _test_client():
 
     The app's lifespan (MQTT, automation engine, health monitoring, etc.)
     starts once for the entire e2e test session and shuts down after all
-    tests complete.
+    tests complete.  The app uses the isolated test database set above.
     """
     from fastapi.testclient import TestClient
     from wled_controller.main import app
@@ -30,6 +59,9 @@ def _test_client():
     with TestClient(app, raise_server_exceptions=False) as c:
         yield c
 
+    # Clean up temp directory after all e2e tests finish
+    shutil.rmtree(_e2e_tmp, ignore_errors=True)
+
 
 @pytest.fixture
 def client(_test_client):
@@ -63,6 +95,7 @@ def _clear_stores():
         (deps.get_sync_clock_store, "get_all", "delete"),
         (deps.get_automation_store, "get_all", "delete"),
         (deps.get_scene_preset_store, "get_all", "delete"),
+        (deps.get_asset_store, "get_all_assets", "delete_asset"),
     ]
     for getter, list_method, delete_method in store_clearers:
         try: