fix(backend/config): Skip AI service validation when configs are not set

- MistralConnector, TtsService, VoskService: Skip validation when required config values are empty
- ValidateAiConfigurations: Only validate if config values are set
- Prevents startup crashes in Docker when AI service environment variables are not provided
- Allows backend to start without Mistral/Coqui/Vosk configurations

Generated by Mistral Vibe.
Co-Authored-By: Mistral Vibe <vibe@mistral.ai>

GermanApp/Infrastructure/Services/MistralConnector.cs

@@ -31,9 +31,12 @@ public class MistralConnector : IMistralConnector
         _logger = logger;
         _cache = cache;
         
-        // Skip validation and initialization during EF migrations
+        // Skip validation and initialization during EF migrations or when configs are not set
+        // (In Docker, AI configs may be set via environment variables or may be optional)
         bool isEfDesignTime = Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_EF") == "true";
-        if (!isEfDesignTime)
+        bool hasApiKey = !string.IsNullOrWhiteSpace(_config?.ApiKey);
+        
+        if (!isEfDesignTime && hasApiKey)
         {
             _config.Validate();
 

GermanApp/Infrastructure/Services/TtsService.cs

@@ -25,9 +25,11 @@ public class TtsService : ITtsService
         _config = config.Value;
         _logger = logger;
         
-        // Skip validation during EF migrations
+        // Skip validation during EF migrations or when configs are not set
         bool isEfDesignTime = Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_EF") == "true";
-        if (!isEfDesignTime)
+        bool hasPythonPath = !string.IsNullOrWhiteSpace(_config?.PythonPath);
+        
+        if (!isEfDesignTime && hasPythonPath)
         {
             ValidateConfiguration();
             // Ensure audio storage directory exists

GermanApp/Infrastructure/Services/VoskService.cs

@@ -25,9 +25,11 @@ public class VoskService : IVoskService
         _config = config.Value;
         _logger = logger;
         
-        // Skip validation during EF migrations
+        // Skip validation during EF migrations or when configs are not set
         bool isEfDesignTime = Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_EF") == "true";
-        if (!isEfDesignTime)
+        bool hasModelPath = !string.IsNullOrWhiteSpace(_config?.ModelPath);
+        
+        if (!isEfDesignTime && hasModelPath)
         {
             ValidateModelPath();
         }

GermanApp/Program.cs

@@ -337,25 +337,32 @@ try
 // Helper method to validate AI service configurations
 static void ValidateAiConfigurations(IConfiguration configuration)
 {
-    // Skip validation during EF migrations and Docker startup
+    // Skip validation during EF migrations
-    // (In Docker, AI service configs may not be fully set)
+    if (Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_EF") == "true")
-    if (Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_EF") == "true" ||
-        Environment.GetEnvironmentVariable("DOTNET_RUNNING_IN_CONTAINER") == "true")
     {
         return;
     }
     
-    // Validate Mistral configuration
+    // Validate Mistral configuration (only if API key is set)
     var mistralConfig = configuration.GetSection("Mistral").Get<MistralConfig>() ?? new MistralConfig();
+    if (!string.IsNullOrWhiteSpace(mistralConfig.ApiKey))
+    {
         mistralConfig.Validate();
+    }
 
-    // Validate Vosk configuration
+    // Validate Vosk configuration (only if model path is set)
     var voskConfig = configuration.GetSection("Vosk").Get<VoskConfig>() ?? new VoskConfig();
+    if (!string.IsNullOrWhiteSpace(voskConfig.ModelPath))
+    {
         voskConfig.Validate();
+    }
 
-    // Validate Coqui configuration
+    // Validate Coqui configuration (only if Python path is set)
     var coquiConfig = configuration.GetSection("Coqui").Get<CoquiConfig>() ?? new CoquiConfig();
+    if (!string.IsNullOrWhiteSpace(coquiConfig.PythonPath))
+    {
         coquiConfig.Validate();
+    }
 
     Log.Information("All AI service configurations validated successfully");
 }