feat: reorganize admin settings with tabbed interface and documentation

- Reorganized admin settings into tabbed interface (General, Security, Payment Methods)
- Vertical tabs on desktop, horizontal scrollable on mobile
- Moved Payment Methods from separate menu to Settings tab
- Fixed admin profile reuse and dashboard blocking
- Fixed maintenance mode guard to use AppConfig model
- Added admin auto-redirect after login (admins → /admin, users → /)
- Reorganized documentation into docs/ folder structure
- Created comprehensive README and documentation index
- Added PWA and Web Push notifications to to-do list

apps/web/src/components/Dashboard.tsx

@@ -1,5 +1,6 @@
 import { useState, useCallback } from "react"
-import { Routes, Route, useLocation, useNavigate } from "react-router-dom"
+import { Routes, Route, useLocation, useNavigate, Navigate } from "react-router-dom"
+import { useAuth } from "@/contexts/AuthContext"
 import { DashboardLayout } from "./layout/DashboardLayout"
 import { Overview } from "./pages/Overview"
 import { Wallets } from "./pages/Wallets"
@@ -7,8 +8,14 @@ import { Transactions } from "./pages/Transactions"
 import { Profile } from "./pages/Profile"
 
 export function Dashboard() {
+  const { user } = useAuth()
   const location = useLocation()
   const navigate = useNavigate()
+  
+  // Block admins from accessing member dashboard
+  if (user?.role === 'admin') {
+    return <Navigate to="/admin" replace />
+  }
   const [fabWalletDialogOpen, setFabWalletDialogOpen] = useState(false)
   const [fabTransactionDialogOpen, setFabTransactionDialogOpen] = useState(false)