Add UI settings API and improve context initialization

- Add /settings/ui GET and PUT endpoints for UI settings
- Improve ThemeContext with better initialization and auto accent handling
- Update SidebarContext with expanded state persistence
- Fix context initialization in ModulesContext and ViewModeContext
- Update components to use improved theme/sidebar contexts

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

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

frontend/src/contexts/SidebarContext.tsx

@@ -1,5 +1,6 @@
 import { createContext, useContext, useState, useEffect, useCallback } from 'react';
 import type { ReactNode } from 'react';
+import { useAuth } from './AuthContext';
 
 export type SidebarMode = 'collapsed' | 'expanded' | 'toggle' | 'dynamic';
 
@@ -21,6 +22,7 @@ interface SidebarContextType {
 const SidebarContext = createContext<SidebarContextType | undefined>(undefined);
 
 export function SidebarProvider({ children }: { children: ReactNode }) {
+  const { token } = useAuth();
   const [userCollapsed, setUserCollapsed] = useState(true);
   const [isMobileOpen, setIsMobileOpen] = useState(false);
   const [sidebarMode, setSidebarModeState] = useState<SidebarMode>('toggle');
@@ -31,19 +33,29 @@ export function SidebarProvider({ children }: { children: ReactNode }) {
   useEffect(() => {
     const loadSidebarMode = async () => {
       try {
-        const token = localStorage.getItem('token');
-        if (!token) return;
+        if (!token) {
+          setSidebarModeState('toggle');
+          setShowLogo(false);
+          return;
+        }
 
-        const response = await fetch('/api/v1/settings', {
-          headers: { 'Authorization': `Bearer ${token} ` }
+        const response = await fetch('/api/v1/settings/ui', {
+          headers: { 'Authorization': `Bearer ${token}` }
         });
         if (response.ok) {
           const data = await response.json();
+          const parseBool = (val: any, defaultVal: boolean): boolean => {
+            if (val === undefined || val === null) return defaultVal;
+            if (val === true || val === 'true' || val === 'True' || val === 1 || val === '1') return true;
+            if (val === false || val === 'false' || val === 'False' || val === 0 || val === '0') return false;
+            return defaultVal;
+          };
+
           if (data.sidebar_mode && ['collapsed', 'expanded', 'toggle', 'dynamic'].includes(data.sidebar_mode)) {
             setSidebarModeState(data.sidebar_mode as SidebarMode);
           }
           if (data.show_logo !== undefined) {
-            setShowLogo(data.show_logo === true);
+            setShowLogo(parseBool(data.show_logo, false));
           }
         }
       } catch (error) {
@@ -51,7 +63,7 @@ export function SidebarProvider({ children }: { children: ReactNode }) {
       }
     };
     loadSidebarMode();
-  }, []);
+  }, [token]);
 
   // Compute isCollapsed based on mode
   const isCollapsed = sidebarMode === 'collapsed' ? true :
@@ -78,11 +90,11 @@ export function SidebarProvider({ children }: { children: ReactNode }) {
 
   const setSidebarMode = useCallback(async (mode: SidebarMode) => {
     try {
-      const token = localStorage.getItem('token');
+      if (!token) return;
       const response = await fetch('/api/v1/settings/sidebar_mode', {
         method: 'PUT',
         headers: {
-          'Authorization': `Bearer ${token} `,
+          'Authorization': `Bearer ${token}`,
           'Content-Type': 'application/json',
         },
         body: JSON.stringify({ value: mode }),
@@ -94,7 +106,7 @@ export function SidebarProvider({ children }: { children: ReactNode }) {
     } catch (error) {
       console.error('Failed to save sidebar mode:', error);
     }
-  }, []);
+  }, [token]);
 
   return (
     <SidebarContext.Provider