fix(pos): corregir error 'state is not defined' y favicon 404

- catalog.js: state → nav (variable correcta del catalogo)
- vsClearAll: resetea nav en vez de state inexistente
- favicon.ico: sirve icon-192.png del PWA

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

pos/app.py

@@ -52,6 +52,10 @@ def create_app():
 
     from flask import render_template, send_from_directory, jsonify, g
 
+    @app.route('/favicon.ico')
+    def favicon():
+        return send_from_directory('static/pwa', 'icon-192.png', mimetype='image/png')
+
     @app.route('/pos/login')
     def pos_login():
         return render_template('login.html',

pos/static/js/catalog.js

@@ -927,11 +927,11 @@
         var modelText = vsModel.options[vsModel.selectedIndex].text;
         var engineText = vsEngine.options[vsEngine.selectedIndex].text;
 
-        state.brand = { id: parseInt(vsBrand.value), name: brandText };
-        state.model = { id: parseInt(vsModel.value), name: modelText };
-        state.year = { id: parseInt(vsYear.value), value: yearText };
-        state.engine = { id_mye: parseInt(myeId), name: engineText };
-        state.level = 'categories';
+        nav.brand = { id: parseInt(vsBrand.value), name: brandText };
+        nav.model = { id: parseInt(vsModel.value), name: modelText };
+        nav.year = { id: parseInt(vsYear.value), year: yearText };
+        nav.engine = { id_mye: parseInt(myeId), name: engineText };
+        nav.level = 'categories';
 
         loadCategories();
 
@@ -952,7 +952,7 @@
         vsEngine.disabled = true;
         vsClear.style.display = 'none';
 
-        state = { level: 'brands', brand: null, model: null, year: null, engine: null, category: null, group: null, page: 1, totalPages: 1 };
+        nav.level = 'brands'; nav.brand = null; nav.model = null; nav.year = null; nav.engine = null; nav.category = null; nav.group = null; currentPage = 1;
         loadBrands();
     }