Enforced model validation

app/MindWork AI Studio/Assistants/I18N/allTexts.lua

@@ -4636,6 +4636,9 @@ UI_TEXT_CONTENT["AISTUDIO::DIALOGS::TRANSCRIPTIONPROVIDERDIALOG::T3703662664"] =
 -- Model selection
 UI_TEXT_CONTENT["AISTUDIO::DIALOGS::TRANSCRIPTIONPROVIDERDIALOG::T416738168"] = "Model selection"
 
+-- Please select a transcription model.
+UI_TEXT_CONTENT["AISTUDIO::DIALOGS::TRANSCRIPTIONPROVIDERDIALOG::T794751523"] = "Please select a transcription model."
+
 -- Host
 UI_TEXT_CONTENT["AISTUDIO::DIALOGS::TRANSCRIPTIONPROVIDERDIALOG::T808120719"] = "Host"
 

app/MindWork AI Studio/Dialogs/TranscriptionProviderDialog.razor

@@ -90,7 +90,7 @@
                             <MudSelect Disabled="@this.IsNoneProvider" @bind-Value="@this.DataModel" Label="@T("Model")"
                                        OpenIcon="@Icons.Material.Filled.FaceRetouchingNatural"
                                        AdornmentColor="Color.Info" Adornment="Adornment.Start"
-                                       Validation="@this.providerValidation.ValidatingModel">
+                                       Validation="@this.ValidateSelectedModel">
                                 @foreach (var model in this.availableModels)
                                 {
                                     <MudSelectItem Value="@model">

app/MindWork AI Studio/Dialogs/TranscriptionProviderDialog.razor.cs

@@ -216,7 +216,16 @@ public partial class TranscriptionProviderDialog : MSGComponentBase, ISecretId
     {
         await this.form.Validate();
         this.dataAPIKeyStorageIssue = string.Empty;
-        
+
+        // Manually validate the model selection (needed when no models are loaded
+        // and the MudSelect is not rendered):
+        var modelValidationError = this.ValidateSelectedModel(this.DataModel);
+        if (!string.IsNullOrWhiteSpace(modelValidationError))
+        {
+            this.dataIssues = [..this.dataIssues, modelValidationError];
+            this.dataIsValid = false;
+        }
+
         // When the data is not valid, we don't store it:
         if (!this.dataIsValid)
             return;
@@ -243,7 +252,28 @@ public partial class TranscriptionProviderDialog : MSGComponentBase, ISecretId
     {
         if (this.DataLLMProvider is LLMProviders.SELF_HOSTED && string.IsNullOrWhiteSpace(manuallyModel))
             return T("Please enter a transcription model name.");
-        
+
+        return null;
+    }
+
+    private string? ValidateSelectedModel(Model model)
+    {
+        // Exception for self-hosted whisper.cpp - no model selection needed:
+        if (this.DataLLMProvider is LLMProviders.SELF_HOSTED && this.DataHost is Host.WHISPER_CPP)
+            return null;
+
+        // For manually entered models, this validation doesn't apply:
+        if (this.DataLLMProvider.IsTranscriptionModelProvidedManually(this.DataHost))
+            return null;
+
+        // For NONE providers, no validation is needed yet:
+        if (this.DataLLMProvider is LLMProviders.NONE)
+            return null;
+
+        // Check if a model is selected:
+        if (model == default)
+            return T("Please select a transcription model.");
+
         return null;
     }