feat: module toggles in POS config and Instance Manager

- Add GET/PUT /pos/api/config/modules endpoints in POS config_bp.py
- Update sidebar.js to filter nav items based on enabled modules
- Add Modules section to POS config.html with toggles for WhatsApp, Marketplace, MercadoLibre
- Add module load/save logic to POS config.js
- Preload modules in app-init.js for sidebar caching

- Add tenant module management to Instance Manager
  - get_tenant_modules / update_tenant_modules in tenant_service.py
  - GET/PUT /api/tenants/<id>/modules endpoints in tenants_bp.py
  - Add modules modal to manager index.html
  - Add module editing UI and logic to manager.js
  - Add toggle-switch CSS to manager.css

manager/static/js/manager.js

@@ -188,6 +188,7 @@ async function loadDemos() {
             <td><a href="https://${escapeHtml(d.subdomain)}.nexusautoparts.com.mx/pos/login" target="_blank" style="color:var(--accent)">${escapeHtml(d.subdomain)}</a></td>
             <td>${d.demo_days_left !== null ? d.demo_days_left + " días" : "N/A"}</td>
             <td>
+                <button class="btn-icon" onclick="openModulesModal(${d.id}, '${escapeHtml(d.name)}')" title="Módulos"><i class="fas fa-cubes" style="color:var(--accent)"></i></button>
                 <button class="btn-icon" onclick="resetTenant(${d.id})" title="Resetear"><i class="fas fa-undo"></i></button>
                 <button class="btn-icon" onclick="toggleTenant(${d.id}, ${!d.is_active})" title="${d.is_active ? "Desactivar" : "Activar"}"><i class="fas fa-${d.is_active ? "pause" : "play"}"></i></button>
                 <button class="btn-icon" onclick="confirmDelete(${d.id}, '${escapeHtml(d.name)}')" title="Eliminar"><i class="fas fa-trash" style="color:var(--danger)"></i></button>
@@ -254,6 +255,7 @@ async function loadTenants(withStats = false) {
             <td>${t.is_active ? tag("Activo", "success") : tag("Inactivo", "danger")}</td>
             <td>${formatDate(t.created_at)}</td>
             <td>
+                <button class="btn-icon" onclick="openModulesModal(${t.id}, '${escapeHtml(t.name)}')" title="Módulos"><i class="fas fa-cubes" style="color:var(--accent)"></i></button>
                 <button class="btn-icon" onclick="resetTenant(${t.id})" title="Resetear datos"><i class="fas fa-undo"></i></button>
                 <button class="btn-icon" onclick="toggleTenant(${t.id}, ${!t.is_active})" title="${t.is_active ? "Desactivar" : "Activar"}"><i class="fas fa-${t.is_active ? "pause" : "play"}"></i></button>
                 <button class="btn-icon" onclick="confirmDelete(${t.id}, '${escapeHtml(t.name)}')" title="Eliminar"><i class="fas fa-trash" style="color:var(--danger)"></i></button>
@@ -475,5 +477,59 @@ function copyText(text) {
     navigator.clipboard.writeText(text).then(() => toast("Copiado al portapapeles", "success"));
 }
 
+// ─── Modules ───────────────────────────────────────────────────────────────
+let currentModulesTenantId = null;
+
+async function openModulesModal(tenantId, name) {
+    currentModulesTenantId = tenantId;
+    document.getElementById("modules-modal-title").textContent = `Módulos — ${escapeHtml(name)}`;
+    document.getElementById("modules-modal").style.display = "flex";
+
+    // Load current state
+    const res = await api(`/api/tenants/${tenantId}/modules`);
+    if (res && res.status === 200) {
+        const m = res.data.data;
+        document.getElementById("mod-whatsapp").checked = m.whatsapp !== false;
+        document.getElementById("mod-marketplace").checked = m.marketplace !== false;
+        document.getElementById("mod-meli").checked = m.meli !== false;
+    } else {
+        toast("Error al cargar módulos", "error");
+    }
+}
+
+function closeModulesModal() {
+    document.getElementById("modules-modal").style.display = "none";
+    currentModulesTenantId = null;
+}
+
+async function saveModules() {
+    if (!currentModulesTenantId) return;
+    const btn = document.getElementById("modules-save-btn");
+    const originalText = btn.innerHTML;
+    btn.innerHTML = `<i class="fas fa-spinner fa-spin"></i> Guardando...`;
+    btn.disabled = true;
+
+    const payload = {
+        whatsapp: document.getElementById("mod-whatsapp").checked,
+        marketplace: document.getElementById("mod-marketplace").checked,
+        meli: document.getElementById("mod-meli").checked,
+    };
+
+    const res = await api(`/api/tenants/${currentModulesTenantId}/modules`, {
+        method: "PUT",
+        body: payload
+    });
+
+    if (res && res.status === 200) {
+        toast("Módulos actualizados", "success");
+        closeModulesModal();
+    } else {
+        toast(res?.data?.error || "Error al guardar", "error");
+    }
+
+    btn.innerHTML = originalText;
+    btn.disabled = false;
+}
+
 // ─── Init ──────────────────────────────────────────────────────────────────
 document.addEventListener("DOMContentLoaded", initAuth);