feat(admin/usuarios): agregar usuario globalmente desde admin

El admin global ahora puede crear usuarios directamente desde
/admin/usuarios sin depender de que un owner los invite.

Backend:
- Nuevo endpoint POST /usuarios/global (controller + service)
- Valida límite de usuarios del plan del tenant destino
- Si el email ya existe, agrega membership al tenant destino
- Si no existe, crea user con temp password + membership
- Schema Zod: email, nombre, role, tenantId, supervisorUserId?

Frontend:
- Botón 'Agregar Usuario' en /admin/usuarios
- Formulario con: nombre, email, rol, empresa
- Hook useCreateUsuarioGlobal con invalidación de queries

apps/web/app/(dashboard)/admin/usuarios/page.tsx

@@ -3,11 +3,11 @@
 import { useState, useEffect } from 'react';
 import { DashboardShell } from '@/components/layouts/dashboard-shell';
 import { Card, CardContent, CardHeader, CardTitle, Button, Input, Label, Select, SelectContent, SelectItem, SelectTrigger, SelectValue } from '@horux/shared-ui';
-import { useAllUsuarios, useUpdateUsuarioGlobal, useDeleteUsuarioGlobal } from '@/lib/hooks/use-usuarios';
+import { useAllUsuarios, useCreateUsuarioGlobal, useUpdateUsuarioGlobal, useDeleteUsuarioGlobal } from '@/lib/hooks/use-usuarios';
 import { getTenants, type Tenant } from '@/lib/api/tenants';
 import { useAuthStore } from '@/stores/auth-store';
 import { isGlobalAdminRfc } from '@horux/shared';
-import { Users, Pencil, Trash2, Shield, Eye, Calculator, Building2, X, Check, UserCog, UserCheck, User, Briefcase } from 'lucide-react';
+import { Users, Pencil, Trash2, Shield, Eye, Calculator, Building2, X, Check, UserCog, UserCheck, User, Briefcase, Plus } from 'lucide-react';
 import { cn } from '@horux/shared-ui';
 
 // Mapa de roles + fallback defensivo. El fork despacho introduce roles
@@ -43,6 +43,15 @@ export default function AdminUsuariosPage() {
   const [editingUser, setEditingUser] = useState<EditingUser | null>(null);
   const [filterTenant, setFilterTenant] = useState<string>('all');
   const [searchTerm, setSearchTerm] = useState('');
+  const [showCreateForm, setShowCreateForm] = useState(false);
+  const [createFormData, setCreateFormData] = useState({
+    email: '',
+    nombre: '',
+    role: 'contador' as 'contador' | 'visor' | 'auxiliar' | 'supervisor' | 'cliente',
+    tenantId: '',
+  });
+
+  const createUsuario = useCreateUsuarioGlobal();
 
   const isGlobal = isGlobalAdminRfc(currentUser?.tenantRfc, currentUser?.role, currentUser?.platformRoles);
 
@@ -86,6 +95,26 @@ export default function AdminUsuariosPage() {
     }
   };
 
+  const handleCreate = async (e: React.FormEvent) => {
+    e.preventDefault();
+    if (!createFormData.tenantId) {
+      alert('Selecciona una empresa');
+      return;
+    }
+    try {
+      await createUsuario.mutateAsync({
+        email: createFormData.email,
+        nombre: createFormData.nombre,
+        role: createFormData.role,
+        tenantId: createFormData.tenantId,
+      });
+      setCreateFormData({ email: '', nombre: '', role: 'contador', tenantId: '' });
+      setShowCreateForm(false);
+    } catch (err: any) {
+      alert(err.response?.data?.error || err.message || 'Error al crear usuario');
+    }
+  };
+
   const filteredUsuarios = usuarios?.filter(u => {
     const matchesTenant = filterTenant === 'all' || u.tenantId === filterTenant;
     const matchesSearch = !searchTerm ||
@@ -152,18 +181,104 @@ export default function AdminUsuariosPage() {
           </CardContent>
         </Card>
 
-        {/* Stats */}
-        <div className="flex items-center gap-4">
-          <div className="flex items-center gap-2">
-            <Users className="h-5 w-5" />
-            <span className="font-medium">{filteredUsuarios?.length || 0} usuarios</span>
-          </div>
-          <div className="flex items-center gap-2 text-muted-foreground">
-            <Building2 className="h-4 w-4" />
-            <span className="text-sm">{Object.keys(groupedByTenant || {}).length} empresas</span>
+        {/* Stats + Acción */}
+        <div className="flex items-center justify-between">
+          <div className="flex items-center gap-4">
+            <div className="flex items-center gap-2">
+              <Users className="h-5 w-5" />
+              <span className="font-medium">{filteredUsuarios?.length || 0} usuarios</span>
+            </div>
+            <div className="flex items-center gap-2 text-muted-foreground">
+              <Building2 className="h-4 w-4" />
+              <span className="text-sm">{Object.keys(groupedByTenant || {}).length} empresas</span>
+            </div>
           </div>
+          <Button onClick={() => setShowCreateForm(true)}>
+            <Plus className="h-4 w-4 mr-2" />
+            Agregar Usuario
+          </Button>
         </div>
 
+        {/* Formulario de creación */}
+        {showCreateForm && (
+          <Card>
+            <CardHeader className="py-3">
+              <CardTitle className="text-base">Nuevo Usuario</CardTitle>
+            </CardHeader>
+            <CardContent>
+              <form onSubmit={handleCreate} className="space-y-4">
+                <div className="grid gap-4 md:grid-cols-2">
+                  <div className="space-y-2">
+                    <Label htmlFor="create-nombre">Nombre</Label>
+                    <Input
+                      id="create-nombre"
+                      value={createFormData.nombre}
+                      onChange={(e) => setCreateFormData({ ...createFormData, nombre: e.target.value })}
+                      placeholder="Juan Pérez"
+                      required
+                    />
+                  </div>
+                  <div className="space-y-2">
+                    <Label htmlFor="create-email">Email</Label>
+                    <Input
+                      id="create-email"
+                      type="email"
+                      value={createFormData.email}
+                      onChange={(e) => setCreateFormData({ ...createFormData, email: e.target.value })}
+                      placeholder="juan@empresa.com"
+                      required
+                    />
+                  </div>
+                </div>
+                <div className="grid gap-4 md:grid-cols-2">
+                  <div className="space-y-2">
+                    <Label htmlFor="create-role">Rol</Label>
+                    <Select
+                      value={createFormData.role}
+                      onValueChange={(v) => setCreateFormData({ ...createFormData, role: v as any })}
+                    >
+                      <SelectTrigger>
+                        <SelectValue />
+                      </SelectTrigger>
+                      <SelectContent>
+                        <SelectItem value="contador">Contador</SelectItem>
+                        <SelectItem value="visor">Visor</SelectItem>
+                        <SelectItem value="auxiliar">Auxiliar</SelectItem>
+                        <SelectItem value="supervisor">Supervisor</SelectItem>
+                        <SelectItem value="cliente">Cliente</SelectItem>
+                      </SelectContent>
+                    </Select>
+                  </div>
+                  <div className="space-y-2">
+                    <Label htmlFor="create-tenant">Empresa</Label>
+                    <Select
+                      value={createFormData.tenantId}
+                      onValueChange={(v) => setCreateFormData({ ...createFormData, tenantId: v })}
+                    >
+                      <SelectTrigger>
+                        <SelectValue placeholder="Selecciona empresa" />
+                      </SelectTrigger>
+                      <SelectContent>
+                        {tenants.map(t => (
+                          <SelectItem key={t.id} value={t.id}>{t.nombre}</SelectItem>
+                        ))}
+                      </SelectContent>
+                    </Select>
+                  </div>
+                </div>
+                <div className="flex gap-2 justify-end">
+                  <Button type="button" variant="outline" onClick={() => setShowCreateForm(false)}>
+                    Cancelar
+                  </Button>
+                  <Button type="submit" disabled={createUsuario.isPending}>
+                    {createUsuario.isPending ? 'Creando...' : 'Crear Usuario'}
+                  </Button>
+                </div>
+              </form>
+            </CardContent>
+          </Card>
+        )}
+
         {/* Users by tenant */}
         {isLoading ? (
           <Card>

apps/web/lib/api/usuarios.ts

@@ -26,6 +26,11 @@ export async function getAllUsuarios(): Promise<UserListItem[]> {
   return response.data;
 }
 
+export async function createUsuarioGlobal(data: UserInvite & { tenantId: string }): Promise<UserListItem> {
+  const response = await apiClient.post<UserListItem>('/usuarios/global', data);
+  return response.data;
+}
+
 export async function updateUsuarioGlobal(id: string, data: UserUpdate): Promise<UserListItem> {
   const response = await apiClient.patch<UserListItem>(`/usuarios/global/${id}`, data);
   return response.data;

apps/web/lib/hooks/use-usuarios.ts

@@ -47,6 +47,17 @@ export function useAllUsuarios() {
   });
 }
 
+export function useCreateUsuarioGlobal() {
+  const queryClient = useQueryClient();
+  return useMutation({
+    mutationFn: (data: UserInvite & { tenantId: string }) => usuariosApi.createUsuarioGlobal(data),
+    onSuccess: () => {
+      queryClient.invalidateQueries({ queryKey: ['usuarios', 'global'] });
+      queryClient.invalidateQueries({ queryKey: ['usuarios'] });
+    },
+  });
+}
+
 export function useUpdateUsuarioGlobal() {
   const queryClient = useQueryClient();
   return useMutation({