FEAT-12a: provider-agnostic sale-ad AI core - AiOptions (env-only), German prompt builder w/ few-shot, OpenAI-compatible chat-completions client (no SDK)

GerbilManagerWebAPI/SaleAd/AiOptions.cs

@@ -0,0 +1,30 @@
+namespace GerbilManagerWebAPI.SaleAd
+{
+    /// <summary>
+    /// FEAT-12a: provider-agnostic AI configuration (section "AI").
+    ///
+    /// Values come from ENVIRONMENT VARIABLES or user-secrets — NEVER from a
+    /// committed appsettings file (Julian's directive). Env-var names:
+    ///   AI__BaseUrl, AI__ApiKey, AI__Model
+    ///
+    /// Any endpoint that speaks the OpenAI-compatible chat-completions shape works:
+    ///   Google Gemini : https://generativelanguage.googleapis.com/v1beta/openai
+    ///   Groq          : https://api.groq.com/openai/v1
+    ///   Mistral       : https://api.mistral.ai/v1
+    ///   Ollama (lokal): http://&lt;host&gt;:11434/v1   (ApiKey beliebig, z. B. "ollama")
+    /// </summary>
+    public sealed class AiOptions
+    {
+        public const string SectionName = "AI";
+
+        public string? BaseUrl { get; set; }
+        public string? ApiKey { get; set; }
+        public string? Model { get; set; }
+
+        /// <summary>All three settings present -> the sale-ad endpoint is live.</summary>
+        public bool IsConfigured =>
+            !string.IsNullOrWhiteSpace(BaseUrl)
+            && !string.IsNullOrWhiteSpace(ApiKey)
+            && !string.IsNullOrWhiteSpace(Model);
+    }
+}