Feat: persist project tree hierarchy

Backend/internal/httpx/api_project_routes.go

@@ -79,6 +79,68 @@ func (routes apiRoutes) handleCreateProjectFolder(w http.ResponseWriter, r *http
 	})
 }
 
+func (routes apiRoutes) handleProjectTreeFolders(w http.ResponseWriter, r *http.Request) {
+	projectID := strings.TrimSpace(chi.URLParam(r, "projectId"))
+	if projectID == "" {
+		WriteError(w, http.StatusBadRequest, RequestIDFromContext(r.Context()), "invalid_request", "Project ID is required.")
+		return
+	}
+
+	folders, err := routes.bootstrapService().GetProjectTreeFolders(r.Context(), projectID)
+	if err != nil {
+		routes.writeProjectFolderError(w, r, err)
+		return
+	}
+
+	WriteJSON(w, http.StatusOK, map[string]any{
+		"data": map[string]any{
+			"projectId": projectID,
+			"folders":   folders,
+		},
+		"meta": map[string]any{
+			"resource": "project-tree-folders",
+		},
+	})
+}
+
+func (routes apiRoutes) handleCreateProjectTreeFolder(w http.ResponseWriter, r *http.Request) {
+	projectID := strings.TrimSpace(chi.URLParam(r, "projectId"))
+	if projectID == "" {
+		WriteError(w, http.StatusBadRequest, RequestIDFromContext(r.Context()), "invalid_request", "Project ID is required.")
+		return
+	}
+
+	payload, ok := decodeProjectFolderRequest(w, r)
+	if !ok {
+		return
+	}
+
+	payload.Name = strings.TrimSpace(payload.Name)
+	payload.ParentFolderID = strings.TrimSpace(payload.ParentFolderID)
+	if payload.Name == "" {
+		WriteError(w, http.StatusBadRequest, RequestIDFromContext(r.Context()), "invalid_request", "Folder name is required.")
+		return
+	}
+
+	result, err := routes.bootstrapService().CreateProjectTreeFolder(r.Context(), bootstrapservice.CreateProjectFolderInput{
+		ProjectID:      projectID,
+		ParentFolderID: payload.ParentFolderID,
+		Name:           payload.Name,
+	})
+	if err != nil {
+		routes.writeProjectFolderError(w, r, err)
+		return
+	}
+
+	WriteJSON(w, http.StatusCreated, map[string]any{
+		"data": result,
+		"meta": map[string]any{
+			"resource":  "project-tree-folder-create",
+			"persisted": true,
+		},
+	})
+}
+
 func (routes apiRoutes) writeProjectFolderError(w http.ResponseWriter, r *http.Request, err error) {
 	switch {
 	case errors.Is(err, bootstrapservice.ErrProjectNotFound), errors.Is(err, bootstrapservice.ErrProjectFolderNotFound):