Fix parsing of boolean (false) excerpts

Calendar/Service/StringOrBooleanConverter.cs

@@ -0,0 +1,30 @@
+using System.Text.Json;
+using System.Text.Json.Serialization;
+
+namespace ChrisKaczor.HomeMonitor.Calendar.Service;
+
+public class StringOrBooleanConverter : JsonConverter<string>
+{
+    public override string Read(ref Utf8JsonReader reader, Type typeToConvert, JsonSerializerOptions options)
+    {
+        return reader.TokenType switch
+        {
+            JsonTokenType.True => string.Empty,
+            JsonTokenType.False => string.Empty,
+            JsonTokenType.String => reader.GetString() ?? string.Empty,
+            _ => throw new JsonException($"Unexpected token type: {reader.TokenType}")
+        };
+    }
+
+    public override void Write(Utf8JsonWriter writer, string value, JsonSerializerOptions options)
+    {
+        if (bool.TryParse(value, out var boolValue))
+        {
+            writer.WriteBooleanValue(boolValue);
+        }
+        else
+        {
+            writer.WriteStringValue(value);
+        }
+    }
+}