feat: Add branding change prompts and corresponding translations for restart notifications

tests/unit/test_config.py

@@ -9,11 +9,14 @@ from webdrop_bridge.config import Config, ConfigurationError
 
 
 @pytest.fixture(autouse=True)
-def clear_env():
+def clear_env(tmp_path):
     """Clear environment variables before each test to avoid persistence."""
     # Save current env
     saved_env = os.environ.copy()
 
+    # Isolate runtime branding state from the developer machine
+    os.environ["WEBDROP_BRANDING_DIR"] = str(tmp_path / "branding")
+
     # Clear relevant variables
     for key in list(os.environ.keys()):
         if key.startswith(