fix: update test fixtures for VendorTheme and CustomerPreferences schemas

- Update VendorTheme fixture to use new colors dict structure
- Update theme tests to check colors dict instead of individual fields
- Update CustomerPreferencesUpdate test for preferred_language field

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

tests/integration/middleware/conftest.py

@@ -93,8 +93,15 @@ def vendor_with_theme(db, middleware_test_company):
     # Add custom theme
     theme = VendorTheme(
         vendor_id=vendor.id,
-        primary_color="#FF5733",
-        secondary_color="#33FF57",
+        theme_name="custom",
+        colors={
+            "primary": "#FF5733",
+            "secondary": "#33FF57",
+            "accent": "#ec4899",
+            "background": "#ffffff",
+            "text": "#1f2937",
+            "border": "#e5e7eb",
+        },
         logo_url="/static/vendors/themedvendor/logo.png",
         favicon_url="/static/vendors/themedvendor/favicon.ico",
         custom_css="body { background: #FF5733; }",

tests/integration/middleware/test_theme_loading_flow.py

@@ -347,8 +347,14 @@ class TestThemeLoadingFlow:
 
         theme = VendorTheme(
             vendor_id=vendor_with_custom_domain.id,
-            primary_color="#123456",
-            secondary_color="#654321",
+            colors={
+                "primary": "#123456",
+                "secondary": "#654321",
+                "accent": "#ec4899",
+                "background": "#ffffff",
+                "text": "#1f2937",
+                "border": "#e5e7eb",
+            },
         )
         db.add(theme)
         db.commit()