Add project files.

Data/WeatherForecast.cs

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+namespace LiveChat.Data
+{
+	public class WeatherForecast
+	{
+		public DateOnly Date { get; set; }
+
+		public int TemperatureC { get; set; }
+
+		public int TemperatureF => 32 + (int)(TemperatureC / 0.5556);
+
+		public string? Summary { get; set; }
+	}
+}

Data/WeatherForecastService.cs

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+namespace LiveChat.Data
+{
+	public class WeatherForecastService
+	{
+		private static readonly string[] Summaries = new[]
+		{
+		"Freezing", "Bracing", "Chilly", "Cool", "Mild", "Warm", "Balmy", "Hot", "Sweltering", "Scorching"
+	};
+
+		public Task<WeatherForecast[]> GetForecastAsync(DateOnly startDate)
+		{
+			return Task.FromResult(Enumerable.Range(1, 5).Select(index => new WeatherForecast
+			{
+				Date = startDate.AddDays(index),
+				TemperatureC = Random.Shared.Next(-20, 55),
+				Summary = Summaries[Random.Shared.Next(Summaries.Length)]
+			}).ToArray());
+		}
+	}
+}