Initial commit of the ClosedXML library

Establishes the foundational structure, core Excel functionality, and tooling.

- Implements base components for cells, ranges, columns, and rows.
- Integrates a custom calculation engine with a wide range of Excel functions.
- Adds comprehensive support for styling, conditional formatting, data validation, comments, pictures, and charts.
- Configures build setup, project metadata (NuGet), and developer guidelines.
- Includes editor and Git attributes for consistent code style and line endings.

ClosedXML_Examples/Ranges/AddingRowToTables.cs

@@ -0,0 +1,56 @@
+using ClosedXML.Excel;
+using System;
+using System.IO;
+using System.Linq;
+
+namespace ClosedXML_Examples.Ranges
+{
+    public class AddingRowToTables : IXLExample
+    {
+        #region Methods
+
+        // Public
+        public void Create(String filePath)
+        {
+            string tempFile = ExampleHelper.GetTempFilePath(filePath);
+            try
+            {
+                new BasicTable().Create(tempFile);
+                var wb = new XLWorkbook(tempFile);
+                var ws = wb.Worksheets.First();
+
+                var firstCell = ws.FirstCellUsed();
+                var lastCell = ws.LastCellUsed();
+                var range = ws.Range(firstCell.Address, lastCell.Address);
+                range.FirstRow().Delete(); // Deleting the "Contacts" header (we don't need it for our purposes)
+
+                // We want to use a theme for table, not the hard coded format of the BasicTable
+                range.Clear(XLClearOptions.AllFormats);
+                // Put back the date and number formats
+                range.Column(4).Style.NumberFormat.NumberFormatId = 15;
+                range.Column(5).Style.NumberFormat.Format = "$ #,##0";
+
+                var table = range.CreateTable(); // You can also use range.AsTable() if you want to
+
+                ws.Cell("Q6000").Value = "dummy value";
+
+                var row = table.DataRange.InsertRowsBelow(1).First();
+
+                wb.SaveAs(filePath);
+            }
+            finally
+            {
+                if (File.Exists(tempFile))
+                {
+                    File.Delete(tempFile);
+                }
+            }
+        }
+
+        // Private
+
+        // Override
+
+        #endregion Methods
+    }
+}