feat: add auth UI to nav — login/logout button, bodega link

Shows business name + logout button when authenticated.
Shows login link when not authenticated. Adds bodega to nav links.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

dashboard/nav.js

@@ -21,12 +21,23 @@
         if ((h === '/admin.html' || h === '/admin') && (p === '/admin.html' || p === '/admin')) return true;
         if ((h === '/diagramas' || h === '/diagrams.html') && (p === '/diagramas' || p === '/diagrams.html')) return true;
         if ((h === '/customer-landing.html') && (p === '/customer-landing.html')) return true;
+        if ((h === '/captura') && (p === '/captura')) return true;
+        if ((h === '/pos') && (p === '/pos')) return true;
+        if ((h === '/cuentas') && (p === '/cuentas')) return true;
+        if ((h === '/tienda') && (p === '/tienda')) return true;
+        if ((h === '/bodega') && (p === '/bodega')) return true;
+        if ((h === '/demo' || h === '/demo.html') && (p === '/demo' || p === '/demo.html')) return true;
         return false;
     }
 
     var navLinks = [
-        { label: 'Cat\u00e1logo', href: '/' },
-        { label: 'Diagramas', href: '/diagramas' },
+        { label: 'Demo', href: '/demo' },
+        { label: 'Tienda', href: '/tienda' },
+        { label: 'Cat\u00e1logo', href: '/index.html' },
+        { label: 'Captura', href: '/captura' },
+        { label: 'POS', href: '/pos' },
+        { label: 'Cuentas', href: '/cuentas' },
+        { label: 'Bodega', href: '/bodega' },
         { label: 'Admin', href: '/admin' }
     ];
 
@@ -99,6 +110,16 @@
         +     '">'
         +       linksHTML
         +     '</nav>'
+        // Auth section
+        +     '<div id="nav-auth" style="display:flex;align-items:center;gap:0.75rem;flex-shrink:0;">'
+        +       '<span id="nav-user-name" style="color:var(--text-secondary);font-size:0.85rem;"></span>'
+        +       '<a id="nav-auth-btn" href="/login.html" style="'
+        +           'text-decoration:none;font-size:0.85rem;font-weight:500;'
+        +           'color:var(--bg);background:var(--accent);'
+        +           'padding:0.4rem 1rem;border-radius:6px;'
+        +           'transition:opacity 0.2s;'
+        +       '">Iniciar Sesi\u00f3n</a>'
+        +     '</div>'
         +   '</div>'
         + '</header>';
 
@@ -106,4 +127,29 @@
     if (target) {
         target.innerHTML = html;
     }
+
+    // Auth state
+    var token = localStorage.getItem('access_token');
+    if (token) {
+        try {
+            var payload = JSON.parse(atob(token.split('.')[1]));
+            var nameEl = document.getElementById('nav-user-name');
+            var btnEl = document.getElementById('nav-auth-btn');
+            if (nameEl && payload.business_name) {
+                nameEl.textContent = payload.business_name;
+            } else if (nameEl) {
+                nameEl.textContent = payload.role || '';
+            }
+            if (btnEl) {
+                btnEl.textContent = 'Salir';
+                btnEl.href = '#';
+                btnEl.onclick = function(e) {
+                    e.preventDefault();
+                    localStorage.removeItem('access_token');
+                    localStorage.removeItem('refresh_token');
+                    window.location.href = '/login.html';
+                };
+            }
+        } catch(e) {}
+    }
 })();