feat(openai): 完善 Chat 与 Responses 参数转发

原生 Chat/Responses 改为透明转发，保留标准工具结构并保护调用方显式参数。补齐 Responses 到 Chat 的兼容转换、协议路由边界、完整响应和流式事件，并同步更新 Swagger、回归测试与真实验收脚本。

验证：
- cd apps/api && env -u AI_GATEWAY_TEST_DATABASE_URL go test ./... -count=1
- pnpm openapi
- pnpm lint
- pnpm test
- pnpm build
- gofmt -l 无输出
- git diff --check 通过

风险：
- Chat 回退无法等价表达的 Responses 原生能力现在会返回 unsupported_response_parameter
- 真实供应商 E2E 因本地没有已启用的平台模型候选而未完成

apps/api/internal/clients/openai.go

@@ -54,10 +54,14 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 			return Response{}, normalizeErr
 		}
 		body = normalizedBody
-		applyOpenAIChatReasoningParams(body, request.Candidate)
+		if err := applyOpenAIChatReasoningParamsWithSource(body, request.Candidate, openAIAdaptationSource(request, endpointKind)); err != nil {
+			return Response{}, err
+		}
 		body = FilterOpenAIChatRequestBody(body)
 	} else if request.Kind == "responses" {
-		applyOpenAIResponsesReasoningParams(body, request.Candidate)
+		if err := applyOpenAIResponsesReasoningParamsWithSource(body, request.Candidate, request.OriginalBody); err != nil {
+			return Response{}, err
+		}
 		body = FilterOpenAIResponsesRequestBody(body)
 		if _, hasInput := body["input"]; !hasInput {
 			if messages, hasMessages := request.Body["messages"]; hasMessages {
@@ -79,8 +83,9 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 	responseStartedAt := time.Now()
 	correctionScope := newParameterCorrectionScope(request, endpointKind)
 	correctionEnabled := endpointKind == "chat.completions" || endpointKind == "responses"
+	protectedCorrections := callerProtectedCorrectionParameters(request, endpointKind)
 	if correctionEnabled {
-		c.Corrections.apply(correctionScope, body)
+		c.Corrections.apply(correctionScope, body, protectedCorrections)
 	}
 	provisionalRules := make([]parameterCorrectionRule, 0, 2)
 	seenCorrectionErrors := make(map[string]struct{})
@@ -96,6 +101,7 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 		}
 		req.Header.Set("Content-Type", contentType)
 		req.Header.Set("Authorization", "Bearer "+apiKey)
+		applyUpstreamIdempotency(req, request)
 		if err := notifySubmissionStarted(request); err != nil {
 			return Response{}, err
 		}
@@ -119,7 +125,7 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 			return Response{}, annotateResponseError(upstreamErr, requestIDFromParameterError(upstreamErr), responseStartedAt, time.Now())
 		}
 		seenCorrectionErrors[fingerprint] = struct{}{}
-		rule, safe := deriveParameterCorrection(upstreamErr, body, request.Candidate)
+		rule, safe := deriveParameterCorrection(upstreamErr, body, request.Candidate, protectedCorrections)
 		if !safe || !applyParameterCorrectionRule(body, rule) {
 			return Response{}, annotateResponseError(upstreamErr, requestIDFromParameterError(upstreamErr), responseStartedAt, time.Now())
 		}
@@ -142,7 +148,7 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 		var streamDelta StreamDelta = nativeStreamDelta
 		var adapter *chatResponsesStreamAdapter
 		if request.Kind == "responses" && protocol == ProtocolOpenAIChatCompletions && stream {
-			adapter = newChatResponsesStreamAdapter(request.PublicResponseID, request.Model)
+			adapter = newChatResponsesStreamAdapter(request.PublicResponseID, request.Model, request.Body)
 			streamDelta = func(event StreamDeltaEvent) error { return adapter.delta(event, request.StreamDelta) }
 		}
 		if stream {
@@ -212,6 +218,19 @@ func (c OpenAIClient) Run(ctx context.Context, request Request) (Response, error
 	}, nil
 }
 
+func openAIAdaptationSource(request Request, endpointKind string) map[string]any {
+	if request.OriginalBody == nil || request.Kind != "responses" || endpointKind != "chat.completions" {
+		return request.OriginalBody
+	}
+	out := cloneBody(request.OriginalBody)
+	if reasoning, ok := request.OriginalBody["reasoning"].(map[string]any); ok {
+		if effort, explicit := reasoning["effort"]; explicit {
+			out["reasoning_effort"] = effort
+		}
+	}
+	return out
+}
+
 func normalizeOpenAIImageRequestBody(endpointKind string, body map[string]any, originalBody map[string]any) {
 	if endpointKind != "images.generations" && endpointKind != "images.edits" {
 		return
@@ -541,12 +560,18 @@ func ensureOpenAIStreamUsage(body map[string]any, kind string, stream bool) {
 		return
 	}
 	streamOptions := map[string]any{}
-	if existing, ok := body["stream_options"].(map[string]any); ok {
+	if raw, explicit := body["stream_options"]; explicit {
+		existing, ok := raw.(map[string]any)
+		if !ok {
+			return
+		}
 		for key, value := range existing {
 			streamOptions[key] = value
 		}
 	}
-	streamOptions["include_usage"] = true
+	if _, explicit := streamOptions["include_usage"]; !explicit {
+		streamOptions["include_usage"] = true
+	}
 	body["stream_options"] = streamOptions
 }