refactor: remove deprecated OpenAI models from registry

Drop GPT-4, GPT-4o, GPT-4o mini, GPT-4 Turbo and GPT-3.5 Turbo
entries in favor of the newer GPT-4.1 family.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

Author: stephanj

src/main/java/com/devoxx/genie/service/models/LLMModelRegistryService.java

@@ -254,70 +254,6 @@ private void addOpenAiModels() {
                         .apiKeyUsed(true)
                         .build());
 
-        String gpt4 = GPT_4.toString();
-        models.put(ModelProvider.OpenAI.getName() + ":" + gpt4,
-                LanguageModel.builder()
-                        .provider(ModelProvider.OpenAI)
-                        .modelName(gpt4)
-                        .displayName("GPT 4")
-                        .inputCost(30)
-                        .outputCost(60)
-                        .inputMaxTokens(8_192)
-                        .outputMaxTokens(8_192)
-                        .apiKeyUsed(true)
-                        .build());
-
-        String gpt4o = GPT_4_O.toString();
-        models.put(ModelProvider.OpenAI.getName() + ":" + gpt4o,
-                LanguageModel.builder()
-                        .provider(ModelProvider.OpenAI)
-                        .modelName(gpt4o)
-                        .displayName("GPT 4o")
-                        .inputCost(2.50)
-                        .outputCost(10.00)
-                        .inputMaxTokens(128_000)
-                        .apiKeyUsed(true)
-                        .build());
-
-        String gpt4oMini = GPT_4_O_MINI.toString();
-        models.put(ModelProvider.OpenAI.getName() + ":" + gpt4oMini,
-                LanguageModel.builder()
-                        .provider(ModelProvider.OpenAI)
-                        .modelName(gpt4oMini)
-                        .displayName("GPT 4o mini")
-                        .inputCost(0.15)
-                        .outputCost(0.6)
-                        .inputMaxTokens(128_000)
-                        .outputMaxTokens(16_384)
-                        .apiKeyUsed(true)
-                        .build());
-
-        String gpt4TurboPreview = GPT_4_TURBO_PREVIEW.toString();
-        models.put(ModelProvider.OpenAI.getName() + ":" + gpt4TurboPreview,
-                LanguageModel.builder()
-                        .provider(ModelProvider.OpenAI)
-                        .modelName(gpt4TurboPreview)
-                        .displayName("GPT 4 Turbo")
-                        .inputCost(10)
-                        .outputCost(30)
-                        .inputMaxTokens(128_000)
-                        .outputMaxTokens(4_096)
-                        .apiKeyUsed(true)
-                        .build());
-
-        String gpt35Turbo = GPT_3_5_TURBO.toString();
-        models.put(ModelProvider.OpenAI.getName() + ":" + gpt35Turbo,
-                LanguageModel.builder()
-                        .provider(ModelProvider.OpenAI)
-                        .modelName(gpt35Turbo)
-                        .displayName("GPT 3.5 Turbo")
-                        .inputCost(0.5)
-                        .outputCost(1.5)
-                        .inputMaxTokens(16_385)
-                        .outputMaxTokens(4_096)
-                        .apiKeyUsed(true)
-                        .build());
-
         String gpt41 = GPT_4_1.toString();
         models.put(ModelProvider.OpenAI.getName() + ":" + gpt41,
                 LanguageModel.builder()