feat: govern effective appearance defaults

webui/src/App.tsx

@@ -36,7 +36,7 @@ const DEFAULT_UI_PREFERENCES: UserUiPreferences = {
   reduce_motion: false,
   sticky_section_sidebars: true,
   theme: "system",
-  palette: "default"
+  palette: null
 };
 
 export default function App() {
@@ -390,7 +390,7 @@ export default function App() {
     root.classList.toggle("ui-hide-help-hints", !preferences.show_inline_help_hints);
     root.classList.toggle("ui-reduce-motion", preferences.reduce_motion);
     root.classList.toggle("ui-no-sticky-section-sidebars", !preferences.sticky_section_sidebars);
-    root.dataset.palette = normalizeUiPalette(preferences.palette);
+    root.dataset.palette = normalizeUiPalette(auth?.user.appearance?.palette ?? preferences.palette);
 
     const systemDarkQuery = window.matchMedia?.("(prefers-color-scheme: dark)") ?? null;
     const applyTheme = () => {
@@ -416,7 +416,8 @@ export default function App() {
     auth?.user.ui_preferences?.reduce_motion,
     auth?.user.ui_preferences?.sticky_section_sidebars,
     auth?.user.ui_preferences?.theme,
-    auth?.user.ui_preferences?.palette
+    auth?.user.ui_preferences?.palette,
+    auth?.user.appearance?.palette
   ]);
 
   useEffect(() => {
@@ -720,7 +721,7 @@ function normalizeUiPreferences(value: Partial<UserUiPreferences> | null | undef
     reduce_motion: Boolean(value?.reduce_motion ?? DEFAULT_UI_PREFERENCES.reduce_motion),
     sticky_section_sidebars: Boolean(value?.sticky_section_sidebars ?? DEFAULT_UI_PREFERENCES.sticky_section_sidebars),
     theme,
-    palette: normalizeUiPalette(value?.palette)
+    palette: normalizeOptionalUiPalette(value?.palette)
   };
 }
 
@@ -730,6 +731,10 @@ function normalizeUiPalette(value: UserUiPalette | string | null | undefined): U
     : "default";
 }
 
+function normalizeOptionalUiPalette(value: UserUiPalette | string | null | undefined): UserUiPalette | null {
+  return value == null ? null : normalizeUiPalette(value);
+}
+
 function mergeWebModules(localModules: PlatformWebModule[], remoteModules: PlatformWebModule[]): PlatformWebModule[] {
   if (remoteModules.length === 0) return localModules;
   const seen = new Set(localModules.map((module) => module.id));