Version: 0.9.73.dev.260505

后端：
1.阶段 5 course 服务边界落地
- 新增 cmd/course 独立进程入口，落地 services/course dao/rpc/sv
- 新增 gateway/client/course、shared/contracts/course 和 shared/ports course port
- 将 /api/v1/course/* HTTP 门面切到 course zrpc，gateway 只保留鉴权、限流、幂等、文件读取和响应透传
- 保留 course 迁移期直写 schedule_events / schedules 权限，维持课程导入两个表同事务写入语义
- 为 course parse-image 补 bytes RPC 契约和 gRPC 消息大小配置，兼容课表图片上传
- 补充 course.rpc 示例配置与阶段 5 文档基线、切流点、残留依赖和 smoke 记录

backend/services/course/rpc/errors.go

@@ -0,0 +1,84 @@
+package rpc
+
+import (
+	"errors"
+	"log"
+	"strings"
+
+	"github.com/LoveLosita/smartflow/backend/respond"
+	coursesv "github.com/LoveLosita/smartflow/backend/services/course/sv"
+	"google.golang.org/genproto/googleapis/rpc/errdetails"
+	"google.golang.org/grpc/codes"
+	"google.golang.org/grpc/status"
+)
+
+const courseErrorDomain = "smartflow.course"
+
+// grpcErrorFromServiceError 负责把 course 内部错误转换为 gRPC status。
+//
+// 职责边界：
+// 1. respond.Response 保留项目内部 status/info，供 gateway 反解；
+// 2. 图片解析哨兵错误转换为历史 HTTP 兼容错误码；
+// 3. 未分类错误只暴露通用内部错误，详细信息留在服务日志。
+func grpcErrorFromServiceError(err error) error {
+	if err == nil {
+		return nil
+	}
+	var resp respond.Response
+	if errors.As(err, &resp) {
+		return grpcErrorFromResponse(resp)
+	}
+	switch {
+	case errors.Is(err, coursesv.ErrCourseImageParserUnavailable):
+		return grpcErrorFromResponse(respond.Response{Status: "50003", Info: "course image parser is not configured"})
+	case errors.Is(err, coursesv.ErrCourseImageTooLarge):
+		return grpcErrorFromResponse(respond.Response{Status: "40064", Info: "course image too large"})
+	case errors.Is(err, coursesv.ErrCourseImageUnsupportedMIME):
+		return grpcErrorFromResponse(respond.Response{Status: "40065", Info: "unsupported course image format"})
+	case errors.Is(err, coursesv.ErrCourseImageEmpty):
+		return grpcErrorFromResponse(respond.Response{Status: "40066", Info: "course image is empty"})
+	}
+	log.Printf("course rpc internal error: %v", err)
+	return status.Error(codes.Internal, "course service internal error")
+}
+
+func grpcErrorFromResponse(resp respond.Response) error {
+	code := grpcCodeFromRespondStatus(resp.Status)
+	message := strings.TrimSpace(resp.Info)
+	if message == "" {
+		message = strings.TrimSpace(resp.Status)
+	}
+	st := status.New(code, message)
+	detail := &errdetails.ErrorInfo{
+		Domain: courseErrorDomain,
+		Reason: resp.Status,
+		Metadata: map[string]string{
+			"info": resp.Info,
+		},
+	}
+	withDetails, err := st.WithDetails(detail)
+	if err != nil {
+		return st.Err()
+	}
+	return withDetails.Err()
+}
+
+func grpcCodeFromRespondStatus(statusValue string) codes.Code {
+	switch strings.TrimSpace(statusValue) {
+	case respond.MissingToken.Status, respond.InvalidToken.Status, respond.InvalidClaims.Status,
+		respond.ErrUnauthorized.Status, respond.WrongTokenType.Status, respond.UserLoggedOut.Status:
+		return codes.Unauthenticated
+	case respond.CourseNotBelongToUser.Status:
+		return codes.PermissionDenied
+	case respond.MissingParam.Status, respond.WrongParamType.Status, respond.ParamTooLong.Status,
+		respond.WrongUserID.Status, respond.WrongCourseID.Status, respond.WrongCourseInfo.Status,
+		respond.InsertCourseTwice.Status, respond.ScheduleConflict.Status, respond.InvalidSectionNumber.Status,
+		respond.InvalidWeekOrDayOfWeek.Status, respond.InvalidSectionRange.Status,
+		respond.TimeOutOfRangeOfThisSemester.Status:
+		return codes.InvalidArgument
+	}
+	if strings.HasPrefix(strings.TrimSpace(statusValue), "5") {
+		return codes.Internal
+	}
+	return codes.InvalidArgument
+}