feat: implement base application layout with NavigationRail and DevExtreme data grid integration

frontend/src/store/useAppStore.ts

@@ -1,4 +1,5 @@
 import { create } from 'zustand';
+import { persist, createJSONStorage } from 'zustand/middleware';
 
 interface ConnectionConfig {
   host: string;
@@ -23,7 +24,9 @@ interface AppState {
   setActiveTable: (table: string | null) => void;
 }
 
-export const useAppStore = create<AppState>((set) => ({
+export const useAppStore = create<AppState>()(
+  persist(
+    (set) => ({
       darkMode: true,
       activeTab: 'explorer',
       activeDatabase: null,
@@ -36,4 +39,16 @@ export const useAppStore = create<AppState>((set) => ({
       clearConnection: () => set({ connection: null, connected: false, activeDatabase: null, activeTable: null }),
       setActiveDatabase: (db) => set({ activeDatabase: db, activeTable: null }),
       setActiveTable: (table) => set({ activeTable: table }),
-}));
+    }),
+    {
+      name: 'mariavel-storage',
+      storage: createJSONStorage(() => localStorage),
+      // Only persist connection and connected status
+      partialize: (state) => ({ 
+        connection: state.connection, 
+        connected: state.connected,
+        darkMode: state.darkMode 
+      }),
+    }
+  )
+);