Added support for images (#609)

app/MindWork AI Studio/Provider/Perplexity/ProviderPerplexity.cs

@@ -9,7 +9,7 @@ using AIStudio.Settings;
 
 namespace AIStudio.Provider.Perplexity;
 
-public sealed class ProviderPerplexity() : BaseProvider("https://api.perplexity.ai/", LOGGER)
+public sealed class ProviderPerplexity() : BaseProvider(LLMProviders.PERPLEXITY, "https://api.perplexity.ai/", LOGGER)
 {
     private static readonly ILogger<ProviderPerplexity> LOGGER = Program.LOGGER_FACTORY.CreateLogger<ProviderPerplexity>();
 
@@ -49,24 +49,7 @@ public sealed class ProviderPerplexity() : BaseProvider("https://api.perplexity.
         var apiParameters = this.ParseAdditionalApiParameters();
         
         // Build the list of messages:
-        var messages = await chatThread.Blocks.BuildMessages(async n => new TextMessage()
-        {
-            Role = n.Role switch
-            {
-                ChatRole.USER => "user",
-                ChatRole.AI => "assistant",
-                ChatRole.AGENT => "assistant",
-                ChatRole.SYSTEM => "system",
-
-                _ => "user",
-            },
-
-            Content = n.Content switch
-            {
-                ContentText text => await text.PrepareTextContentForAI(),
-                _ => string.Empty,
-            }
-        });
+        var messages = await chatThread.Blocks.BuildMessagesUsingNestedImageUrlAsync(this.Provider, chatModel);
         
         // Prepare the Perplexity HTTP chat request:
         var perplexityChatRequest = JsonSerializer.Serialize(new ChatCompletionAPIRequest