Add default theme management to branding settings and admin interface

src/contexts/BrandingContext.jsx

@@ -1,23 +1,29 @@
 import { createContext, useContext, useState, useEffect, useCallback } from 'react';
 import api from '../services/api';
+import { useTheme } from './ThemeContext';
 
 const BrandingContext = createContext();
 
 export function BrandingProvider({ children }) {
+  const { applyBrandingDefault } = useTheme();
   const [branding, setBranding] = useState({
     appName: 'Redlight',
     hasLogo: false,
     logoUrl: null,
+    defaultTheme: null,
   });
 
   const fetchBranding = useCallback(async () => {
     try {
       const res = await api.get('/branding');
       setBranding(res.data);
+      if (res.data.defaultTheme) {
+        applyBrandingDefault(res.data.defaultTheme);
+      }
     } catch {
       // keep defaults
     }
-  }, []);
+  }, [applyBrandingDefault]);
 
   useEffect(() => {
     fetchBranding();

src/contexts/ThemeContext.jsx

@@ -4,20 +4,33 @@ const ThemeContext = createContext(null);
 
 export function ThemeProvider({ children }) {
   const [theme, setThemeState] = useState(() => {
-    return localStorage.getItem('theme') || 'dark';
+    // Personal preference > last known branding default > hardcoded fallback
+    return localStorage.getItem('theme') || localStorage.getItem('branding-default-theme') || 'dark';
   });
 
   useEffect(() => {
     document.documentElement.setAttribute('data-theme', theme);
-    localStorage.setItem('theme', theme);
   }, [theme]);
 
+  // Called by user intentionally (Settings page etc.) — saves as personal preference
   const setTheme = useCallback((newTheme) => {
+    localStorage.setItem('theme', newTheme);
     setThemeState(newTheme);
   }, []);
 
+  // Called by BrandingContext after loading the admin-configured default theme.
+  // Only takes effect when the user has no personal preference stored.
+  const applyBrandingDefault = useCallback((newDefault) => {
+    if (!newDefault) return;
+    localStorage.setItem('branding-default-theme', newDefault);
+    if (!localStorage.getItem('theme')) {
+      setThemeState(newDefault);
+      document.documentElement.setAttribute('data-theme', newDefault);
+    }
+  }, []);
+
   return (
-    <ThemeContext.Provider value={{ theme, setTheme }}>
+    <ThemeContext.Provider value={{ theme, setTheme, applyBrandingDefault }}>
       {children}
     </ThemeContext.Provider>
   );