feat: cashier/counter reports, service-order & remission flows, Rached migration utils

- Add "Mis cortes de caja" report for cashiers/counters with sales detail.
- Cash register history scoped to own cuts for non-admin roles; new /register/<id>/sales endpoint.
- Remove dashboard from cashier menu; add Reports to cashier/counter.
- Service orders: assign mechanic, budget field, invoice flag, counter/cashier can add items/remissions, convert to remission.
- Remission notes module (UI, CSS, courier, counter remissions).
- Customer hard-delete and vehicle/customer linkage in workshop.
- POS: always show search results, compact payment grid, credit validation, tier pricing (5%/10%), ticket with customer/folio.
- Inventory: CSV template with sku_secondary, alias import.
- Rached migration scripts and DB migrations.
- Version-bump cached JS/CSS query strings.

Excludes local Rached session tokens/captures (rached_*.json / rached_*.txt).

pos/templates/inventory.html

@@ -192,7 +192,7 @@
           <h1 class="page-header__title">Inventario</h1>
         </div>
         <div class="page-header__actions">
-          <button class="btn btn--ghost" onclick="document.getElementById('bulkImportModal').classList.add('is-open')">
+          <button class="btn btn--ghost" id="btnHeaderImport" onclick="document.getElementById('bulkImportModal').classList.add('is-open')">
             <svg viewBox="0 0 24 24"><path d="M21 15v4a2 2 0 0 1-2 2H5a2 2 0 0 1-2-2v-4"/><polyline points="17 8 12 3 7 8"/><line x1="12" y1="3" x2="12" y2="15"/></svg>
             Importar CSV
           </button>
@@ -204,7 +204,7 @@
             <svg viewBox="0 0 24 24"><polyline points="23 4 23 10 17 10"/><path d="M20.49 15a9 9 0 1 1-.38-4.93"/></svg>
             Sincronizar
           </button>
-          <button class="btn btn--primary" onclick="showCreateModal()">
+          <button class="btn btn--primary" id="btnHeaderNewProduct" onclick="showCreateModal()">
             <svg viewBox="0 0 24 24"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg>
             Nuevo Producto
           </button>
@@ -336,7 +336,7 @@
               <svg viewBox="0 0 24 24"><circle cx="12" cy="12" r="10"/><line x1="12" y1="6" x2="12" y2="12"/><line x1="16.24" y1="16.24" x2="12" y2="12"/></svg>
               <span id="tierDiscountBadge">Taller -15% · Mayoreo -25%</span>
             </button>
-            <button class="btn btn--primary btn--sm" onclick="showCreateModal()">
+            <button class="btn btn--primary btn--sm" id="btnStockNewProduct" onclick="showCreateModal()">
               <svg viewBox="0 0 24 24"><line x1="12" y1="5" x2="12" y2="19"/><line x1="5" y1="12" x2="19" y2="12"/></svg>
               Nuevo Producto
             </button>
@@ -1018,6 +1018,9 @@
         <button class="inv-modal__close" onclick="document.getElementById('bulkImportModal').classList.remove('is-open')">&times;</button>
       </div>
       <div class="inv-modal__body">
+        <div style="margin-bottom:12px;">
+          <button class="btn btn--ghost btn--sm" onclick="downloadBulkImportTemplate()" type="button">📥 Descargar plantilla CSV</button>
+        </div>
         <div style="margin-bottom:12px;">
           <label style="display:block;margin-bottom:4px;font-size:var(--text-caption);color:var(--color-text-muted);">Archivo CSV o Excel</label>
           <input type="file" id="bulkImportFile" accept=".csv,.xlsx,.xls" style="width:100%;padding:8px;border:1px dashed var(--color-border);border-radius:6px;background:var(--color-surface);color:var(--color-text);" />
@@ -1039,8 +1042,8 @@
         </div>
         <div style="font-size:var(--text-caption);color:var(--color-text-muted);background:var(--color-surface);padding:10px;border-radius:6px;">
           <strong>Columnas esperadas:</strong>
-          <code style="display:block;margin-top:4px;word-break:break-all;">sku, name, brand, price, stock, cost, location, description, category, make, model, year, engine, engine_code</code>
-          <span style="display:block;margin-top:4px;">También se aceptan sinónimos en español: <em>numero_de_parte, nombre, marca, precio, cantidad, costo, ubicacion, categoria, fabricante, modelo, anio, motor, codigo_motor</em></span>
+          <code style="display:block;margin-top:4px;word-break:break-all;">sku, name, brand, price, stock, cost, sku_secondary, description, category, make, model, year, engine, engine_code</code>
+          <span style="display:block;margin-top:4px;">También se aceptan sinónimos en español: <em>numero_de_parte, nombre, marca, precio, cantidad, costo, sku_secundario, categoria, fabricante, modelo, anio, motor, codigo_motor</em></span>
         </div>
         <div id="bulkImportResult" style="margin-top:12px;display:none;"></div>
       </div>
@@ -1058,13 +1061,13 @@
     <button class="banner__dismiss" onclick="document.getElementById('offlineBanner').style.display='none'" aria-label="Cerrar">&times;</button>
   </div>
 
-  <script src="/pos/static/js/i18n.js?v=36" defer></script>
-  <script src="/pos/static/js/app-init.js?v=2" defer></script>
+  <script src="/pos/static/js/i18n.js?v=39" defer></script>
+  <script src="/pos/static/js/app-init.js?v=5" defer></script>
   <script src="/pos/static/js/splash-loader.js?v=33" defer></script>
   <script src="/pos/static/js/pos-utils.js?v=33" defer></script>
-  <script src="/pos/static/js/sidebar.js?v=36" defer></script>
+  <script src="/pos/static/js/sidebar.js?v=44" defer></script>
   <script src="/pos/static/js/virtual-scroll.js?v=33" defer></script>
-  <script src="/pos/static/js/inventory.js?v=34" defer></script>
+  <script src="/pos/static/js/inventory.js?v=37" defer></script>
   <script src="/pos/static/js/offline-banner.js" defer></script>
   <script src="/pos/static/js/sync-engine.js" defer></script>
   <script>if('serviceWorker' in navigator){navigator.serviceWorker.register('/pos/sw.js',{scope:'/pos/'});}</script>