fix(pos): wire buttons in contabilidad, facturacion, inventario, dashboard

- Contabilidad: Nueva Poliza modal + Exportar placeholder
- Facturacion: Nueva Factura modal (sale_id input) + Nota Credito placeholder
- Inventario: click en producto abre detalle con historial
- Dashboard: Ver Detalles navega a paginas relevantes, campana a alertas

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

pos/templates/invoicing.html

@@ -1522,14 +1522,14 @@
             </svg>
             Exportar
           </button>
-          <button class="btn btn--secondary">
+          <button class="btn btn--secondary" onclick="window.notaCreditoPlaceholder()">
             <svg viewBox="0 0 24 24">
               <path d="M9 14l-4-4 4-4"/>
               <path d="M5 10h11a4 4 0 0 1 0 8h-1"/>
             </svg>
             Nota de Crédito
           </button>
-          <button class="btn btn--primary">
+          <button class="btn btn--primary" onclick="window.showNewInvoiceModal()">
             <svg viewBox="0 0 24 24">
               <line x1="12" y1="5" x2="12" y2="19"/>
               <line x1="5" y1="12" x2="19" y2="12"/>
@@ -2699,6 +2699,28 @@
     </div>
   </div>
 
+  <!-- Nueva Factura Modal -->
+  <div id="newInvoiceModalOverlay" style="display:none;position:fixed;inset:0;background:rgba(0,0,0,0.5);z-index:9999;align-items:center;justify-content:center;">
+    <div style="background:var(--color-surface-1);border-radius:var(--radius-lg);width:min(480px,90vw);box-shadow:var(--shadow-lg);">
+      <div style="padding:var(--space-5) var(--space-6);border-bottom:1px solid var(--color-border);display:flex;justify-content:space-between;align-items:center;">
+        <div style="font-family:var(--font-heading);font-size:var(--text-h4);font-weight:var(--heading-weight-primary);">Nueva Factura</div>
+        <button class="btn btn--ghost btn--sm" onclick="window.closeNewInvoiceModal()">&times;</button>
+      </div>
+      <div style="padding:var(--space-6);">
+        <p style="font-size:var(--text-body-sm);color:var(--color-text-muted);margin-bottom:var(--space-4);">Ingrese el ID de la venta para generar el CFDI (Ingreso).</p>
+        <div style="margin-bottom:var(--space-4);">
+          <label style="display:block;font-size:var(--text-caption);color:var(--color-text-muted);margin-bottom:var(--space-1);text-transform:uppercase;letter-spacing:var(--tracking-widest);">ID de Venta</label>
+          <input type="number" id="invoiceSaleId" placeholder="Ej: 1042" style="width:100%;padding:var(--space-2) var(--space-3);border:1px solid var(--color-border);border-radius:var(--radius-md);background:var(--color-surface-2);color:var(--color-text-primary);font-size:var(--text-body-sm);" />
+        </div>
+        <div id="invoiceResult" style="margin-bottom:var(--space-3);"></div>
+      </div>
+      <div style="padding:var(--space-4) var(--space-6);border-top:1px solid var(--color-border);display:flex;justify-content:flex-end;gap:var(--space-3);">
+        <button class="btn btn--ghost" onclick="window.closeNewInvoiceModal()">Cancelar</button>
+        <button class="btn btn--primary" onclick="window.submitNewInvoice()">Generar Factura</button>
+      </div>
+    </div>
+  </div>
+
   <script src="/pos/static/js/app-init.js"></script>
   <script src="/pos/static/js/sidebar.js"></script>
   <script src="/pos/static/js/invoicing.js"></script>