Add unit tests for various services and functionalities

- Implement tests for ChatLine utility methods including color tag detection and stripping.
- Create comprehensive tests for CommandHandler to validate command handling and status updates.
- Add tests for DataMigrationService to ensure correct ANSI to color tag conversion.
- Enhance FileValidationHelperTests with audio file validation tests.
- Introduce ImageToAsciiServiceTests to verify image dimension retrieval.
- Develop IrcMessageFormatterTests for message formatting and color tag conversion.
- Add JwtTokenServiceTests to validate JWT token generation and hashing.
- Implement LinkEmbedServiceTests for URL extraction and Open Graph tag parsing.
- Update EchoHub.Tests.csproj to include necessary project references.

src/EchoHub.Tests/ImageToAsciiServiceTests.cs

@@ -0,0 +1,62 @@
+using EchoHub.Core.Constants;
+using EchoHub.Server.Services;
+using Xunit;
+
+namespace EchoHub.Tests;
+
+public class ImageToAsciiServiceTests
+{
+    [Fact]
+    public void GetDimensions_Small_Returns40x40()
+    {
+        var (w, h) = ImageToAsciiService.GetDimensions("s");
+        Assert.Equal(40, w);
+        Assert.Equal(40, h);
+    }
+
+    [Fact]
+    public void GetDimensions_Large_Returns120x120()
+    {
+        var (w, h) = ImageToAsciiService.GetDimensions("l");
+        Assert.Equal(120, w);
+        Assert.Equal(120, h);
+    }
+
+    [Fact]
+    public void GetDimensions_Default_Returns80x80()
+    {
+        var (w, h) = ImageToAsciiService.GetDimensions("m");
+        Assert.Equal(HubConstants.AsciiArtWidth, w);
+        Assert.Equal(HubConstants.AsciiArtHeightHalfBlock, h);
+    }
+
+    [Fact]
+    public void GetDimensions_Null_ReturnsDefault()
+    {
+        var (w, h) = ImageToAsciiService.GetDimensions(null);
+        Assert.Equal(HubConstants.AsciiArtWidth, w);
+        Assert.Equal(HubConstants.AsciiArtHeightHalfBlock, h);
+    }
+
+    [Fact]
+    public void GetDimensions_CaseInsensitive()
+    {
+        var (w1, h1) = ImageToAsciiService.GetDimensions("S");
+        var (w2, h2) = ImageToAsciiService.GetDimensions("s");
+        Assert.Equal(w1, w2);
+        Assert.Equal(h1, h2);
+
+        var (w3, h3) = ImageToAsciiService.GetDimensions("L");
+        var (w4, h4) = ImageToAsciiService.GetDimensions("l");
+        Assert.Equal(w3, w4);
+        Assert.Equal(h3, h4);
+    }
+
+    [Fact]
+    public void GetDimensions_UnknownSize_ReturnsDefault()
+    {
+        var (w, h) = ImageToAsciiService.GetDimensions("xl");
+        Assert.Equal(HubConstants.AsciiArtWidth, w);
+        Assert.Equal(HubConstants.AsciiArtHeightHalfBlock, h);
+    }
+}