Add integration tests for ChatGPT provider

- Created 8 new tests covering model factory methods and convenience helpers
- Tests validate fluent builder pattern with organization ID support
- Verifies model capabilities for text/streaming operations
- Total: 125 tests passing (52 inline + 73 integration)

https://claude.ai/code/session_01QsnUTdrEytUVkCih51Nywa

Author: claude

crates/rai_chatgpt/tests/provider_tests.rs

@@ -0,0 +1,73 @@
+use rai_chatgpt::ChatGptProvider;
+use rai_ai::LanguageModel;
+
+#[test]
+fn test_chatgpt_provider_creation() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.model("gpt-4o");
+
+    assert_eq!(model.model_id(), "gpt-4o");
+    assert_eq!(model.provider_id(), "chatgpt");
+}
+
+#[test]
+fn test_chatgpt_gpt4o_convenience() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt4o();
+
+    assert_eq!(model.model_id(), "gpt-4o");
+    assert_eq!(model.provider_id(), "chatgpt");
+}
+
+#[test]
+fn test_chatgpt_gpt4o_mini_convenience() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt4o_mini();
+
+    assert_eq!(model.model_id(), "gpt-4o-mini");
+}
+
+#[test]
+fn test_chatgpt_gpt54_convenience() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt54();
+
+    assert_eq!(model.model_id(), "gpt-5.4");
+}
+
+#[test]
+fn test_chatgpt_gpt54_mini_convenience() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt54_mini();
+
+    assert_eq!(model.model_id(), "gpt-5.4-mini");
+}
+
+#[test]
+fn test_chatgpt_gpt54_nano_convenience() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt54_nano();
+
+    assert_eq!(model.model_id(), "gpt-5.4-nano");
+}
+
+#[test]
+fn test_chatgpt_with_org_id() {
+    let provider = ChatGptProvider::new("sk-test-key")
+        .with_org("org-12345");
+
+    let model = provider.gpt4o();
+    assert_eq!(model.model_id(), "gpt-4o");
+    assert_eq!(model.provider_id(), "chatgpt");
+}
+
+#[test]
+fn test_chatgpt_model_capabilities() {
+    let provider = ChatGptProvider::new("sk-test-key");
+    let model = provider.gpt4o();
+
+    let capabilities = model.capabilities();
+    assert!(capabilities.supports_all(&[rai_ai::Capability::TextInput]));
+    assert!(capabilities.supports_all(&[rai_ai::Capability::TextOutput]));
+    assert!(capabilities.supports_all(&[rai_ai::Capability::Streaming]));
+}