Improve usability of QR code login

[nickvergessen]

Option added directly into the account menu

QR code can be configured to be one-time

Only supported with future mobile clients of Android and iOS. Since old ones break, it's disabled by default for now, but will be enabled by default in a future version.
Also the current settings page does not use this, as it's already showing the app password and we can not change the type afterwards.
Expiration time can be configured with an app config.

One time QR Code that expires	Permanent QR code like before this PR

Admin setting to disable app password generation

Default	Disabled

Checklist

• Code is properly formatted
• Sign-off message is added to all commits
• Tests (unit, integration, api and/or acceptance) are included
• Screenshots before/after for front-end changes
• Documentation (manuals or wiki) has been updated or is not required
• Backports requested where applicable (ex: critical bugfixes)
• Labels added where applicable (ex: bug/enhancement, 3. to review, feature component)
• Milestone added for target branch/version (ex: 32.x for stable32)

[CarlSchwan]

does that need translation?

[nickvergessen]

Both should be very temporary as valid devices scanning the code will set a proper name.
But I added it for now

[mahibi]

@nickvergessen Testing with android talk implementation on Sermo i get 403 after removing account and try to login another time:

nextcloud/talk-android#5700 (comment)

1. Login with onetime QR (works)
2. remove account in app
3. Login with new onetime QR for same account

Bug:
"Something went wrong" snackbar is shown. Log is:

2026-01-16 10:02:28.650 11291-11470 okhttp.OkHttpClient     com.nextcloud.talk2                  I  {"ocs":{"meta":{"status":"failure","statuscode":403,"message":"could not get one-time app password"},"data":[]}}
2026-01-16 10:02:28.650 11291-11470 okhttp.OkHttpClient     com.nextcloud.talk2                  I  <-- END HTTP (112-byte body)
2026-01-16 10:02:28.650 11291-11470 NetworkLoginDataSource  com.nextcloud.talk2                  E  Error caught at oneTimePasswordRequest: java.io.IOException: Unexpected code Response{protocol=h2, code=403, message=, url=https://.....yourserverurl......com/ocs/v2.php/core/getapppassword-onetime}

[nickvergessen]

For the record, I responded in chat.
Most likely a problem in the mobile app, it sees to send cookie or other authentication data so the session used is not a one-time session and therefore the endpoint can not be called.