allow adding waiting_for and task_title columns in instance list page

spiffworkflow-backend/src/spiffworkflow_backend/routes/process_instances_controller.py

@@ -298,8 +298,8 @@ def process_instance_report_show(
 def process_instance_report_column_list(
     process_model_identifier: Optional[str] = None,
 ) -> flask.wrappers.Response:
-    """Process_instance_report_column_list."""
     table_columns = ProcessInstanceReportService.builtin_column_options()
+    system_report_column_options = ProcessInstanceReportService.system_report_column_options()
     columns_for_metadata_query = (
         db.session.query(ProcessInstanceMetadataModel.key)
         .order_by(ProcessInstanceMetadataModel.key)
@@ -315,7 +315,7 @@ def process_instance_report_column_list(
     columns_for_metadata_strings = [
         {"Header": i[0], "accessor": i[0], "filterable": True} for i in columns_for_metadata
     ]
-    return make_response(jsonify(table_columns + columns_for_metadata_strings), 200)
+    return make_response(jsonify(table_columns + system_report_column_options + columns_for_metadata_strings), 200)
 
 
 def process_instance_show_for_me(

spiffworkflow-backend/src/spiffworkflow_backend/services/process_instance_report_service.py

@@ -320,7 +320,7 @@ class ProcessInstanceReportService:
 
     @classmethod
     def builtin_column_options(cls) -> list[ReportMetadataColumn]:
-        """Builtin_column_options."""
+        """Columns that are actually in the process instance table."""
         return_value: list[ReportMetadataColumn] = [
             {"Header": "Id", "accessor": "id", "filterable": False},
             {
@@ -339,6 +339,15 @@ class ProcessInstanceReportService:
         ]
         return return_value
 
+    @classmethod
+    def system_report_column_options(cls) -> list[ReportMetadataColumn]:
+        """Columns that are used with certain system reports."""
+        return_value: list[ReportMetadataColumn] = [
+            {"Header": "Task", "accessor": "task_title", "filterable": False},
+            {"Header": "Waiting For", "accessor": "waiting_for", "filterable": False},
+        ]
+        return return_value
+
     @classmethod
     def get_filter_value(cls, filters: list[FilterValue], filter_key: str) -> Any:
         for filter in filters: