feat(workspace): add GET /branches endpoint

internal/workspace/handler_test.go

@@ -49,7 +49,7 @@ func (f *fakeWS) GetCredentialMeta(_ context.Context, _ Caller, _ uuid.UUID) (*C
 }
 
 func (f *fakeWS) ListBranches(_ context.Context, _ Caller, _ uuid.UUID) ([]string, error) {
-	return nil, nil
+	return []string{"main", "develop"}, nil
 }
 
 // fakeResolver 把固定 token 解码为 uuid（沿 internal/project handler_test.go 模式）。
@@ -86,3 +86,26 @@ func TestHandler_CreateWorkspace_Smoke(t *testing.T) {
 	r.ServeHTTP(w, req)
 	require.Equal(t, http.StatusCreated, w.Code)
 }
+
+func TestHandler_ListBranches_Smoke(t *testing.T) {
+	t.Parallel()
+	ws := &fakeWS{}
+	uid := uuid.New()
+	tok := "tok-branches"
+	resolver := &fakeResolver{valid: map[string]uuid.UUID{tok: uid}}
+	h := NewHandler(ws, nil, nil, resolver, fakeAdmin{})
+	r := chi.NewRouter()
+	r.Use(middleware.RequestID)
+	h.Mount(r)
+
+	wsID := uuid.New()
+	req := httptest.NewRequest("GET", "/api/v1/workspaces/"+wsID.String()+"/branches", nil)
+	req.Header.Set("Authorization", "Bearer "+tok)
+	w := httptest.NewRecorder()
+	r.ServeHTTP(w, req)
+	require.Equal(t, http.StatusOK, w.Code)
+
+	var resp branchListResp
+	require.NoError(t, json.NewDecoder(w.Body).Decode(&resp))
+	require.Equal(t, []string{"main", "develop"}, resp.Branches)
+}