refactor: Rename TrueCV to RealCV throughout codebase

- Renamed all directories (TrueCV.* -> RealCV.*)
- Renamed all project files (.csproj)
- Renamed solution file (TrueCV.sln -> RealCV.sln)
- Updated all namespaces in C# and Razor files
- Updated project references
- Updated CSS variable names

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

src/RealCV.Application/Helpers/DateHelpers.cs

@@ -0,0 +1,35 @@
+namespace RealCV.Application.Helpers;
+
+public static class DateHelpers
+{
+    /// <summary>
+    /// Calculates the number of months between two dates.
+    /// </summary>
+    public static int MonthsBetween(DateOnly start, DateOnly end)
+    {
+        return ((end.Year - start.Year) * 12) + (end.Month - start.Month);
+    }
+
+    /// <summary>
+    /// Calculates the number of months between two dates.
+    /// </summary>
+    public static int MonthsBetween(DateTime start, DateTime end)
+    {
+        return ((end.Year - start.Year) * 12) + (end.Month - start.Month);
+    }
+
+    public static DateOnly? ParseDate(string? dateString)
+    {
+        if (string.IsNullOrWhiteSpace(dateString))
+        {
+            return null;
+        }
+
+        if (DateOnly.TryParse(dateString, out var date))
+        {
+            return date;
+        }
+
+        return null;
+    }
+}