feat(project): add workspace_id to issue/requirement with tri-state update

internal/project/issue_service.go

@@ -61,7 +61,8 @@ func (s *issueService) Create(ctx context.Context, c Caller, slug string, in Cre
 	}
 	in1 := &Issue{
 		ID: uuid.New(), ProjectID: p.ID, RequirementID: reqID,
-		Title: in.Title, Description: in.Description,
+		WorkspaceID: in.WorkspaceID,
+		Title:       in.Title, Description: in.Description,
 		AssigneeID: in.AssigneeID, CreatedBy: c.UserID,
 	}
 	out, err := s.createWithRetry(ctx, in1)
@@ -72,6 +73,9 @@ func (s *issueService) Create(ctx context.Context, c Caller, slug string, in Cre
 	if reqID != nil {
 		meta["requirement_id"] = reqID.String()
 	}
+	if in.WorkspaceID != nil {
+		meta["workspace_id"] = in.WorkspaceID.String()
+	}
 	s.recordAudit(ctx, c, "issue.create", out.ID.String(), meta)
 	return out, nil
 }
@@ -165,11 +169,34 @@ func (s *issueService) Update(ctx context.Context, c Caller, slug string, number
 		}
 	}
 
+	// workspace 三态：nil（未提供）/ &uuid.Nil（解绑）/ &id（关联）
+	nextWS := cur.WorkspaceID
+	if in.WorkspaceID != nil {
+		if *in.WorkspaceID == uuid.Nil {
+			nextWS = nil
+		} else {
+			v := *in.WorkspaceID
+			nextWS = &v
+		}
+		auditFrom := "<none>"
+		if cur.WorkspaceID != nil {
+			auditFrom = cur.WorkspaceID.String()
+		}
+		auditTo := "<none>"
+		if nextWS != nil {
+			auditTo = nextWS.String()
+		}
+		if auditFrom != auditTo {
+			changed["from_workspace"] = auditFrom
+			changed["to_workspace"] = auditTo
+		}
+	}
+
 	if len(changed) == 0 {
 		return cur, nil
 	}
 
-	out, err := s.repo.UpdateIssueCore(ctx, cur.ID, title, desc, reqID)
+	out, err := s.repo.UpdateIssueCore(ctx, cur.ID, title, desc, reqID, nextWS)
 	if err != nil {
 		return nil, err
 	}