AI网关新增TTS/重排/审核端点,xAI工具扩展,swagger修缺

- 新端点 /ai/v1/audio/speech(xai.grok-tts)、/rerank(cohere.rerank-v4)、/moderations(OCI Guardrails)
- Responses 放行 code_interpreter 与远程 mcp 工具,web_search/x_search 解除仅非流式限制
- 模型能力映射扩展:TEXT_RERANK→RERANK、TEXT_TO_AUDIO→TTS
- AI 网关文档独立 docs/ai-gateway.md,字段兼容矩阵只列支持项;README 精简引用
- swagger 修缺:135 处响应注解具体化,RawMessage/联合类型统一渲染 AnyJSON,overrides 迁至 docs/.swaggo
- CHANGELOG 0.4.0,版本段不再记日期;DASH_VERSION v0.4.0

internal/service/aigateway_test.go

@@ -61,6 +61,26 @@ type gatewayStubClient struct {
 	passErrs    []error
 	passCalls   int
 	passRegions []string
+
+	speechAudio  []byte
+	speechCT     string
+	speechErr    error
+	rerankRanks  []oci.RerankRank
+	rerankErr    error
+	guardOutcome *oci.GuardrailsOutcome
+	guardErr     error
+}
+
+func (f *gatewayStubClient) GenAiCompatSpeech(ctx context.Context, cred oci.Credentials, region string, body []byte) ([]byte, string, error) {
+	return f.speechAudio, f.speechCT, f.speechErr
+}
+
+func (f *gatewayStubClient) GenAiRerank(ctx context.Context, cred oci.Credentials, region, modelOcid, query string, documents []string, topN *int) ([]oci.RerankRank, error) {
+	return f.rerankRanks, f.rerankErr
+}
+
+func (f *gatewayStubClient) GenAiApplyGuardrails(ctx context.Context, cred oci.Credentials, region, text string) (*oci.GuardrailsOutcome, error) {
+	return f.guardOutcome, f.guardErr
 }
 
 func (f *gatewayStubClient) GenAiCompatResponses(ctx context.Context, cred oci.Credentials, region string, body []byte) ([]byte, error) {