feat(F-194): completed feature

project/apps/admin/src/app/(dashboard)/settings/audit/page.tsx

@@ -1,5 +1,6 @@
 'use client';
 import { useState, useEffect, useCallback, useRef } from 'react';
+import Link from 'next/link';
 import { auditApi, type AuditEntry } from '@/lib/api-client';
 
 const PAGE_SIZE = 50;
@@ -79,6 +80,7 @@ export default function AuditLogPage() {
   return (
     <div className="space-y-6">
       <div>
+        <Link href="/settings" className="text-sm text-[#2D6A4F] hover:underline">← Ajustes</Link>
         <h1 className="text-2xl font-bold text-gray-900">Log de auditoría
           {pollingActive && (
             <span className="ml-3 inline-flex items-center gap-1.5 text-xs text-green-600 font-medium align-middle">

project/apps/admin/src/app/(dashboard)/settings/logs/page.tsx

@@ -1,4 +1,5 @@
 'use client';
+import Link from 'next/link';
 import { ServerLogViewer } from '@/components/ServerLogViewer';
 
 export default function ServerLogsPage() {
@@ -10,6 +11,7 @@ export default function ServerLogsPage() {
   return (
     <div className="space-y-6">
       <div>
+        <Link href="/settings" className="text-sm text-[#2D6A4F] hover:underline">← Ajustes</Link>
         <h1 className="text-2xl font-bold text-gray-900">Logs del servidor</h1>
         <p className="text-sm text-gray-500 mt-0.5">
           Stream en tiempo real via SSE. Las líneas erróneas se resaltan en rojo. Máximo 200 líneas.

project/apps/admin/src/app/(dashboard)/settings/page.tsx

@@ -1,5 +1,6 @@
 'use client';
 import { useState, useEffect } from 'react';
+import Link from 'next/link';
 import { settingsApi, type StoreSettings } from '@/lib/api-client';
 
 type FormData = StoreSettings;
@@ -105,6 +106,17 @@ export default function SettingsPage() {
                 {t.label}
               </button>
             ))}
+            <div className="my-3 border-t border-gray-200" />
+            <p className="px-4 text-xs font-semibold uppercase tracking-wide text-gray-400">Sistema</p>
+            <Link href="/settings/tax-rates" className="flex w-full items-center gap-2 px-4 py-2.5 rounded-xl text-sm font-medium text-gray-600 hover:bg-gray-100 transition-colors">
+              <span>💰</span> IVA
+            </Link>
+            <Link href="/settings/audit" className="flex w-full items-center gap-2 px-4 py-2.5 rounded-xl text-sm font-medium text-gray-600 hover:bg-gray-100 transition-colors">
+              <span>📋</span> Auditoría
+            </Link>
+            <Link href="/settings/logs" className="flex w-full items-center gap-2 px-4 py-2.5 rounded-xl text-sm font-medium text-gray-600 hover:bg-gray-100 transition-colors">
+              <span>🖥️</span> Logs
+            </Link>
           </nav>
 
           {/* Form area */}

project/apps/admin/src/app/(dashboard)/settings/tax-rates/page.tsx

@@ -1,6 +1,7 @@
 'use client';
 import { useState, useEffect, useCallback } from 'react';
 import { taxApi, type TaxRate } from '@/lib/api-client';
+import Link from 'next/link';
 import { RowActions } from '@/components/ui/RowActions';
 
 export default function TaxRatesPage() {
@@ -69,6 +70,7 @@ export default function TaxRatesPage() {
   return (
     <div className="space-y-6">
       <div>
+        <Link href="/settings" className="text-sm text-[#2D6A4F] hover:underline">← Ajustes</Link>
         <h1 className="text-2xl font-bold text-gray-900">Tipos impositivos (IVA)</h1>
         <p className="text-sm text-gray-500 mt-0.5">Configura los tipos de IVA aplicables a los productos.</p>
       </div>

project/apps/admin/src/lib/permissions.ts

@@ -55,10 +55,10 @@ export const NAV_ITEMS: NavItem[] = [
   { href: '/reviews', label: 'Reseñas', icon: '⭐', permission: 'reviews.read' },
   { href: '/cms', label: 'CMS', icon: '📄', permission: 'cms.read' },
   { href: '/users', label: 'Usuarios', icon: '🔐', permission: 'admin-users.read' },
-  { href: '/tax-rates', label: 'IVA', icon: '📊', permission: 'orders.read' },
-  { href: '/audit', label: 'Auditoría', icon: '📋', permission: 'audit.read' },
-  { href: '/logs', label: 'Logs', icon: '🖥️', permission: 'audit.read' },
   { href: '/settings', label: 'Ajustes', icon: '⚙️', permission: 'dashboard' },
+  { href: '/settings/tax-rates', label: 'IVA', icon: '💰', permission: 'orders.read' },
+  { href: '/settings/audit', label: 'Auditoría', icon: '📋', permission: 'audit.read' },
+  { href: '/settings/logs', label: 'Logs', icon: '🖥️', permission: 'audit.read' },
 ];
 
 export function visibleNavItems(role: Role): NavItem[] {

project/apps/pos/src/app/(terminal)/page.tsx

@@ -274,7 +274,7 @@ export default function RegisterPage() {
     setCart((current) => [
       ...current,
       {
-        lineId: `free-${crypto.randomUUID()}`,
+        lineId: `free-${generateIdempotencyKey()}`,
         kind: 'free',
         variantId: null,
         productId: null,

project/apps/pos/src/components/PaymentModal.tsx

@@ -3,6 +3,7 @@
 import { useMemo, useState } from 'react';
 import { formatPrice } from '@/lib/money';
 import type { PaymentAllocation, PaymentMethod } from '@/types/checkout';
+import { generateIdempotencyKey } from '@/lib/idempotency';
 
 interface PaymentModalProps {
   method: PaymentMethod;
@@ -48,7 +49,7 @@ export default function PaymentModal({
       return;
     }
     onAdd({
-      id: crypto.randomUUID(),
+      id: generateIdempotencyKey(),
       methodCode: method.code,
       methodLabel: method.label,
       kind: method.kind,