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

internal/project/issue_service_test.go

@@ -114,3 +114,72 @@ func TestIssueService_Update_BlockedWhenProjectArchived(t *testing.T) {
 	require.True(t, ok)
 	require.Equal(t, errs.CodeProjectArchived, ae.Code)
 }
+
+func TestIssueService_Create_WithWorkspaceID(t *testing.T) {
+	repo := newFakeRepo()
+	owner := uuid.New()
+	seedProject(t, repo, owner)
+	issueSvc, _, spy := newIssueSvc(repo)
+	caller := Caller{UserID: owner}
+
+	wsID := uuid.New()
+	out, err := issueSvc.Create(context.Background(), caller, "demo", CreateIssueInput{
+		Title: "I", WorkspaceID: &wsID,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, out.WorkspaceID)
+	require.Equal(t, wsID, *out.WorkspaceID)
+
+	// 再 Get 一次确认持久化
+	got, err := issueSvc.Get(context.Background(), caller, "demo", out.Number)
+	require.NoError(t, err)
+	require.NotNil(t, got.WorkspaceID)
+	require.Equal(t, wsID, *got.WorkspaceID)
+
+	// audit metadata 包含 workspace_id
+	require.NotEmpty(t, spy.entries)
+	last := spy.entries[len(spy.entries)-1]
+	require.Equal(t, "issue.create", last.Action)
+	require.Equal(t, wsID.String(), last.Metadata["workspace_id"])
+}
+
+func TestIssueService_Update_WorkspaceID_TriState(t *testing.T) {
+	repo := newFakeRepo()
+	owner := uuid.New()
+	seedProject(t, repo, owner)
+	issueSvc, _, _ := newIssueSvc(repo)
+	caller := Caller{UserID: owner}
+
+	wsA := uuid.New()
+	i, err := issueSvc.Create(context.Background(), caller, "demo", CreateIssueInput{
+		Title: "I", WorkspaceID: &wsA,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, i.WorkspaceID)
+	require.Equal(t, wsA, *i.WorkspaceID)
+
+	// 1) nil → 不变（用 Title 强制 changed 非空，走持久化路径，验证 nextWS 不被错误清空）
+	newTitle := "I-renamed"
+	out, err := issueSvc.Update(context.Background(), caller, "demo", i.Number, UpdateIssueInput{Title: &newTitle})
+	require.NoError(t, err)
+	require.Equal(t, newTitle, out.Title)
+	require.NotNil(t, out.WorkspaceID)
+	require.Equal(t, wsA, *out.WorkspaceID)
+
+	// 2) &id（非 Nil）→ 关联到新 workspace
+	wsB := uuid.New()
+	out, err = issueSvc.Update(context.Background(), caller, "demo", i.Number, UpdateIssueInput{
+		WorkspaceID: &wsB,
+	})
+	require.NoError(t, err)
+	require.NotNil(t, out.WorkspaceID)
+	require.Equal(t, wsB, *out.WorkspaceID)
+
+	// 3) &uuid.Nil → 显式解绑
+	nilUUID := uuid.Nil
+	out, err = issueSvc.Update(context.Background(), caller, "demo", i.Number, UpdateIssueInput{
+		WorkspaceID: &nilUUID,
+	})
+	require.NoError(t, err)
+	require.Nil(t, out.WorkspaceID)
+}