feat: 完成模拟交易闭环、App 与 A 股行情接入

统一单入口 Go 工程与前端依赖目录，增加后台供应商配置、候选审核、计划预算、成交冲正、持仓复盘和站内通知。接入策略版本、Python 回测、可配置 A 股公开行情及 zap 文件轮转日志，补充迁移、契约与验证。

internal/service/candidate.go

@@ -0,0 +1,102 @@
+package service
+
+import (
+	"context"
+	"time"
+
+	"git.sundynix.cn/Blizzard/Veyra/internal/apperror"
+	"git.sundynix.cn/Blizzard/Veyra/internal/model"
+	"github.com/google/uuid"
+)
+
+type CandidateRepository interface {
+	List(context.Context, bool, string, int) ([]model.CandidateRevision, error)
+	Detail(context.Context, string, bool) (model.CandidateDetail, error)
+	Create(context.Context, model.CandidateDraftInput, string, string, string, int64) (model.CandidateRevision, error)
+	Transition(context.Context, string, string, model.CandidateActionInput, string, string) (model.CandidateRevision, error)
+}
+type CandidateService struct {
+	repo        CandidateRepository
+	development bool
+}
+
+func NewCandidateService(repo CandidateRepository, development bool) *CandidateService {
+	return &CandidateService{repo: repo, development: development}
+}
+func (s *CandidateService) authorize(actor model.User, admin bool) error {
+	if actor.Status != "ACTIVE" || (admin && actor.Role != "ADMIN") || (!admin && actor.Role != "USER") {
+		return apperror.ErrForbidden
+	}
+	if s == nil || s.repo == nil {
+		return apperror.ErrUnavailable
+	}
+	// Manual simulation publishing is a development capability, not production authorization.
+	if !s.development {
+		return apperror.ErrUnavailable
+	}
+	return nil
+}
+func (s *CandidateService) List(ctx context.Context, actor model.User, admin bool, status string, limit int) ([]model.CandidateRevision, error) {
+	if err := s.authorize(actor, admin); err != nil {
+		return nil, err
+	}
+	if limit < 1 || limit > 100 {
+		return nil, apperror.ErrInvalidInput
+	}
+	switch status {
+	case "", "DRAFT", "PENDING_REVIEW", "PUBLISHED", "RETURNED", "WITHDRAWN":
+	default:
+		return nil, apperror.ErrInvalidInput
+	}
+	if !admin && status != "" {
+		return nil, apperror.ErrInvalidInput
+	}
+	return s.repo.List(ctx, admin, status, limit)
+}
+func (s *CandidateService) Detail(ctx context.Context, actor model.User, id string, admin bool) (model.CandidateDetail, error) {
+	if err := s.authorize(actor, admin); err != nil {
+		return model.CandidateDetail{}, err
+	}
+	if _, err := uuid.Parse(id); err != nil {
+		return model.CandidateDetail{}, apperror.ErrInvalidInput
+	}
+	return s.repo.Detail(ctx, id, admin)
+}
+func (s *CandidateService) Create(ctx context.Context, actor model.User, source, requestID string, input model.CandidateDraftInput, expected int64) (model.CandidateRevision, error) {
+	if err := s.authorize(actor, true); err != nil {
+		return model.CandidateRevision{}, err
+	}
+	if source != "" {
+		if _, err := uuid.Parse(source); err != nil {
+			return model.CandidateRevision{}, apperror.ErrInvalidInput
+		}
+		if expected < 1 {
+			return model.CandidateRevision{}, apperror.ErrInvalidInput
+		}
+	}
+	if _, err := uuid.Parse(requestID); err != nil {
+		return model.CandidateRevision{}, apperror.ErrInvalidInput
+	}
+	if err := model.ValidateDraft(input, time.Now().UTC()); err != nil {
+		return model.CandidateRevision{}, err
+	}
+	return s.repo.Create(ctx, input, actor.ID, requestID, source, expected)
+}
+func (s *CandidateService) Transition(ctx context.Context, actor model.User, id, action, requestID string, input model.CandidateActionInput) (model.CandidateRevision, error) {
+	if err := s.authorize(actor, true); err != nil {
+		return model.CandidateRevision{}, err
+	}
+	if _, err := uuid.Parse(id); err != nil {
+		return model.CandidateRevision{}, apperror.ErrInvalidInput
+	}
+	if _, err := uuid.Parse(requestID); err != nil {
+		return model.CandidateRevision{}, apperror.ErrInvalidInput
+	}
+	if input.ExpectedVersion < 1 {
+		return model.CandidateRevision{}, apperror.ErrInvalidInput
+	}
+	if err := model.ValidateReason(input.Reason); err != nil {
+		return model.CandidateRevision{}, err
+	}
+	return s.repo.Transition(ctx, id, action, input, actor.ID, requestID)
+}