fix: remove anthropic_version from body - AI Core rejects it

llm/aicore.go

@@ -253,7 +253,7 @@ func (c *AICoreClient) CompleteAnthropic(ctx context.Context, model string, mess
 	}
 
 	reqBody := anthropicRequest{
-		AnthropicVersion: "2023-06-01",
+		// AnthropicVersion omitted - SAP AI Core does not accept it in body
 		// Model omitted - AI Core deployment already specifies model
 		MaxTokens: maxTokens,
 		System:    system,

llm/aicore_test.go

@@ -206,8 +206,8 @@ func TestAICoreClient_CompleteAnthropic(t *testing.T) {
 		if err := json.NewDecoder(r.Body).Decode(&req); err != nil {
 			t.Fatalf("decode request: %v", err)
 		}
-		if req.AnthropicVersion != "2023-06-01" {
-			t.Errorf("expected anthropic_version in request")
+		if req.MaxTokens == 0 {
+			t.Errorf("expected max_tokens in request")
 		}
 		if req.System != "You are helpful" {
 			t.Errorf("expected system prompt: %q", req.System)