feat(inventory): list operations in Entradas/Salidas/Traspasos/Ajustes tabs

- Add GET /operations endpoint with filtering by type, pagination, date range
- Join with inventory, employees, branches for rich display
- Add tbody IDs and footer/pagination IDs to operation tables in HTML
- Add loadOperations() JS function with renderOperationRow() per type
- Integrate loadOperations into switchTab for auto-load on tab change
- Update recordPurchase/Adjustment/Transfer to refresh respective lists
- Expose loadOperations globally for HTML inline script access

pos/blueprints/inventory_bp.py

@@ -678,6 +678,110 @@ def api_return():
     return jsonify({'operation_id': op_id, 'message': 'Return recorded'})
 
 
+@inventory_bp.route('/operations', methods=['GET'])
+@require_auth('inventory.view')
+def api_operations():
+    """List inventory operations (purchases, sales, transfers, adjustments).
+    Supports filtering by operation_type, pagination, and date range.
+    """
+    conn = get_tenant_conn(g.tenant_id)
+    cur = conn.cursor()
+
+    op_type = request.args.get('type')
+    page = int(request.args.get('page', 1))
+    per_page = int(request.args.get('per_page', 50))
+    branch_id = request.args.get('branch_id', g.branch_id)
+    date_from = request.args.get('date_from')
+    date_to = request.args.get('date_to')
+    offset = (page - 1) * per_page
+
+    # Build query dynamically
+    where_clauses = ['1=1']
+    params = []
+
+    if op_type:
+        where_clauses.append('io.operation_type = %s')
+        params.append(op_type)
+    if branch_id:
+        where_clauses.append('(io.branch_id = %s OR io.branch_id IS NULL)')
+        params.append(branch_id)
+    if date_from:
+        where_clauses.append('io.created_at >= %s')
+        params.append(date_from)
+    if date_to:
+        where_clauses.append('io.created_at <= %s')
+        params.append(date_to + ' 23:59:59')
+
+    where_sql = ' AND '.join(where_clauses)
+
+    # Get total count
+    cur.execute(f"""
+        SELECT COUNT(*) FROM inventory_operations io
+        WHERE {where_sql}
+    """, params)
+    total = cur.fetchone()[0]
+
+    # Get operations with product and employee info
+    cur.execute(f"""
+        SELECT 
+            io.id,
+            io.operation_type,
+            io.quantity,
+            io.cost_at_time,
+            io.notes,
+            io.created_at,
+            io.employee_id,
+            e.name as employee_name,
+            i.id as inventory_id,
+            i.part_number,
+            i.name as product_name,
+            i.barcode,
+            io.branch_id,
+            b.name as branch_name
+        FROM inventory_operations io
+        LEFT JOIN inventory i ON io.inventory_id = i.id
+        LEFT JOIN employees e ON io.employee_id = e.id
+        LEFT JOIN branches b ON io.branch_id = b.id
+        WHERE {where_sql}
+        ORDER BY io.created_at DESC
+        LIMIT %s OFFSET %s
+    """, params + [per_page, offset])
+
+    rows = cur.fetchall()
+    operations = []
+    for row in rows:
+        operations.append({
+            'id': row[0],
+            'operation_type': row[1],
+            'quantity': row[2],
+            'cost_at_time': float(row[3]) if row[3] else None,
+            'notes': row[4],
+            'created_at': row[5].isoformat() if row[5] else None,
+            'employee_id': row[6],
+            'employee_name': row[7],
+            'inventory_id': row[8],
+            'part_number': row[9],
+            'product_name': row[10],
+            'barcode': row[11],
+            'branch_id': row[12],
+            'branch_name': row[13],
+            'total': float(row[3] * row[2]) if row[3] and row[2] else None
+        })
+
+    cur.close()
+    conn.close()
+
+    return jsonify({
+        'data': operations,
+        'pagination': {
+            'page': page,
+            'per_page': per_page,
+            'total': total,
+            'total_pages': (total + per_page - 1) // per_page
+        }
+    })
+
+
 # ─── Physical Count (two-phase: start → approve) ──────────
 
 @inventory_bp.route('/physical-count/start', methods=['POST'])