Member list uses too much space in local storage

[max-nextcloud]

Describe the bug
As observed in #2518 the member list starts using lots of storage in localstorage if there are many members.

Each member uses several kb of storage:

localStorage.getItem('collectives/pinia/circles/circlesMembers').length
// 282813
const members = JSON.parse(localStorage.getItem('collectives/pinia/circles/circlesMembers'))
JSON.stringify(members.LvrxIVdG4ET9VQwrwSIeW5JQsPIPWxK[0]).length
// 6049

To Reproduce
Steps to reproduce the behavior:

1. Open a collective
2. Open the web dev tools
3. Get the list of members as described above
4. Pick one collective (f.e. using autocomplete on members) and one member to get it's size.

Expected behavior
We should only store what's needed - at most what currently is in member.basedOn.owner (350 bytes for me).

Browsers have 5 Mb of local storage. So with 6k per member we currently cannot handle more than 1k members in total for all collectives of a user. With < 500 bytes on average 1k members would still only consume 10% of storage.

Server details:
cloud.nextcloud.com

• Collectives app version: 4.4.2
• Nextcloud version: 34.0.2

[max-nextcloud]

The easiest quick fix from my point of view would be dropping the details from the circles membership query.

That would remove our ability to detect if the current user is a member of a circle / group inside the collective which we currently use to disallow changing that groups level.

I would suggest to just allow changing everyones settings if the user is an admin - just like in contacts.

[Koc]

We need to do something with avatars existence cache in NcAvatar component, like nextcloud_per_bmV4dGNsb3Vk_user-has-avatar.admin: true. It adds tons of keys

[max-nextcloud]

@Koc I don't quite understand. Looking at that key I would assume there's 1k entries for 1k users. If each entry is < 100 bytes key length... how would that fill the 5 Mb of storage?
The circleMembers with > 5Kb storage per entry seem like a much more likely candidate for me for filling up the storage with 1k members.
What am I missing?