In that case I would do it like this, forget about silenceInitialCommit. That will not work.
1) Just add an onLoad listener on the project and send all sequenceNumbers to a controller handler and save it. Like:
export default class Project extends ProjectModel {
construct(...args) {
super.construct(...args);
this.projectIds = window.o_gantt.projectID === 0 ? [] : [window.o_gantt.projectID];
this.loadProjectsOnly = false;
this.on('load', () => {
const data = [];
this.taskStore.forEach(task => {
data.push({ id: task.id, sequenceNumber: task.sequenceNumber });
});
this.jsonRpc('your_sequence_number_handler', data).then(() => {
//
});
})
}
jsonRpc(url, data) {
2) Make a new routing in the controller to handle the saving of your sequence numbers.
Like:
@http.route('/bryntum_gantt/your_sequence_number_handler', type='json', auth='user', cors="*")
def your_sequence_number_handler(self, data=None, **kw):
data_json = loads(data)
...
I assume you know how to implement this handler yourself, because that is out of the scope of our support. Like adding a new field to the Odoo Task model and save those values in the database etcetera. Most of that is also explained above.
Hope this will help you out.