Added a home page prompt for missing API keys of enterprise providers (#1056)

Co-authored-by: Thorsten Sommer <SommerEngineering@users.noreply.github.com>

app/MindWork AI Studio/Tools/PluginSystem/IUserProvidedAPIKey.cs

@@ -3,7 +3,8 @@ namespace AIStudio.Tools.PluginSystem;
 /// <summary>
 /// Represents a configuration object whose API key is managed by the user, although the object
 /// itself is managed by a configuration plugin. Implemented by all provider kinds which support
-/// the "AllowUserProvidedAPIKey" option, i.e., LLM, embedding, and transcription providers.
+/// the options "AllowUserProvidedAPIKey" and "PromptForUserAPIKey", i.e., LLM, embedding, and
+/// transcription providers. UserProvidedAPIKeyOptions reads both options from a plugin.
 /// </summary>
 public interface IUserProvidedAPIKey
 {
@@ -12,4 +13,10 @@ public interface IUserProvidedAPIKey
     /// locked, enterprise-managed object.
     /// </summary>
     public bool AllowUserProvidedAPIKey { get; }
+
+    /// <summary>
+    /// When set by a configuration plugin, AI Studio asks the user for the API key of this object
+    /// on the home page as long as none is stored. Implies AllowUserProvidedAPIKey.
+    /// </summary>
+    public bool PromptForUserAPIKey { get; }
 }