feat: Add delete and preview functionality for branding in settings dialog and update translations

tests/unit/test_branding_manager.py

@@ -1,6 +1,8 @@
 """Tests for runtime branding template management."""
 
-from webdrop_bridge.config import Config
+import pytest
+
+from webdrop_bridge.config import Config, ConfigurationError
 from webdrop_bridge.core.branding_manager import BrandingManager
 
 
@@ -97,3 +99,28 @@ def test_switching_back_to_default_restores_default_branding(tmp_path):
 
     assert config.app_name == "WebDrop Bridge"
     assert config.branding_display_name == "Default"
+
+
+def test_delete_custom_branding_removes_it(tmp_path):
+    """Custom brandings should be removable while built-ins stay protected."""
+    manager = BrandingManager(base_dir=tmp_path)
+    template = manager.build_template(template_id="Customer B", display_name="Customer B")
+    manager.save_template(template)
+
+    assert manager.has_template("customer_b")
+
+    manager.delete_template("customer_b")
+
+    assert not manager.has_template("customer_b")
+
+
+def test_invalid_logo_file_is_rejected(tmp_path):
+    """Non-existent logo files should not be accepted for saved brandings."""
+    manager = BrandingManager(base_dir=tmp_path)
+
+    with pytest.raises(ConfigurationError):
+        manager.build_template(
+            template_id="customer_c",
+            display_name="Customer C",
+            logo_path=str(tmp_path / "missing-logo.png"),
+        )