feat(workspace): add ListBranches method to WorkspaceService

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

internal/workspace/domain.go

@@ -145,6 +145,7 @@ type WorkspaceService interface {
 
 	UpsertCredential(ctx context.Context, c Caller, wsID uuid.UUID, in UpsertCredentialInput) (*Credential, error)
 	GetCredentialMeta(ctx context.Context, c Caller, wsID uuid.UUID) (*Credential, error)
+	ListBranches(ctx context.Context, c Caller, wsID uuid.UUID) ([]string, error)
 }
 
 // WorktreeService 暴露支线 worktree 的应用服务方法。

internal/workspace/handler_test.go

@@ -48,6 +48,10 @@ func (f *fakeWS) GetCredentialMeta(_ context.Context, _ Caller, _ uuid.UUID) (*C
 	return &Credential{Kind: CredKindNone}, nil
 }
 
+func (f *fakeWS) ListBranches(_ context.Context, _ Caller, _ uuid.UUID) ([]string, error) {
+	return nil, nil
+}
+
 // fakeResolver 把固定 token 解码为 uuid（沿 internal/project handler_test.go 模式）。
 type fakeResolver struct{ valid map[string]uuid.UUID }
 

internal/workspace/workspace_service.go

@@ -328,6 +328,23 @@ func (s *workspaceService) GetCredentialMeta(ctx context.Context, c Caller, wsID
 	return cred, nil
 }
 
+func (s *workspaceService) ListBranches(ctx context.Context, c Caller, wsID uuid.UUID) ([]string, error) {
+	ws, err := s.repo.GetWorkspaceByID(ctx, wsID)
+	if err != nil {
+		return nil, err
+	}
+	if canRead, _, err := s.pa.ResolveByID(ctx, c.UserID, c.IsAdmin, ws.ProjectID); err != nil {
+		return nil, err
+	} else if !canRead {
+		return nil, errs.New(errs.CodeForbidden, "no read access")
+	}
+	cred, err := s.loadDecryptedCredential(ctx, wsID)
+	if err != nil {
+		return nil, err
+	}
+	return s.gitr.ListRemoteBranches(ctx, ws.MainPath, cred)
+}
+
 func (s *workspaceService) encryptForUpsert(wsID uuid.UUID, in UpsertCredentialInput) (*Credential, error) {
 	cred := &Credential{
 		ID:          uuid.New(),

internal/workspace/workspace_service_test.go

@@ -450,3 +450,36 @@ func TestWorkspaceService_Update_DefaultBranch_SameValue_NoGitOps(t *testing.T)
 	require.Empty(t, fg.fetchRemoteBranchCalls)
 	require.Empty(t, fg.checkoutCalls)
 }
+
+func TestWorkspaceService_ListBranches(t *testing.T) {
+	t.Parallel()
+	pa := &fakePA{pid: uuid.New(), canRead: true, canWrite: true}
+	svc, repo := newSvc(t, pa, nil, &fakeGit{})
+	caller := Caller{UserID: uuid.New()}
+
+	wsID := uuid.New()
+	repo.wss[wsID] = &Workspace{
+		ID: wsID, ProjectID: pa.pid, Slug: "ws1",
+		DefaultBranch: "main", MainPath: "/data/ws1/main",
+	}
+
+	branches, err := svc.ListBranches(context.Background(), caller, wsID)
+	require.NoError(t, err)
+	// fakeGit returns nil, nil → empty slice
+	require.Nil(t, branches)
+}
+
+func TestWorkspaceService_ListBranches_NoReadAccess(t *testing.T) {
+	t.Parallel()
+	pa := &fakePA{pid: uuid.New(), canRead: false, canWrite: false}
+	svc, repo := newSvc(t, pa, nil, &fakeGit{})
+	caller := Caller{UserID: uuid.New()}
+
+	wsID := uuid.New()
+	repo.wss[wsID] = &Workspace{
+		ID: wsID, ProjectID: pa.pid, Slug: "ws1",
+	}
+
+	_, err := svc.ListBranches(context.Background(), caller, wsID)
+	require.Error(t, err)
+}