fix(settings): use @update:modelValue so admin switches save again

[ernolf]

Summary

On the Guests admin settings page none of the switches persisted: toggling any switch did nothing on save and it reverted after a reload, and the "Limit guest account creation to the following groups only" switch could not be toggled at all. No PUT /apps/guests/config was ever sent.

Root cause

src/views/GuestSettings.vue wires the save handler to @update:checked:

<NcCheckboxRadioSwitch
    v-model="config.allowExternalStorage"
    type="switch"
    @update:checked="saveConfig">

NcCheckboxRadioSwitch in @nextcloud/vue 9.x emits update:modelValue, not update:checked (the bundled component declares emits: ["update:modelValue"]). So saveConfig() was never called. v-model still updated the local state, so the switch flipped visually while nothing was persisted. The group switch additionally used a one-way :modelValue together with the same dead event, so its state never changed at all.

Regression

This worked before the Vue 3 migration. It broke in 0ed6e335 ("chore: migrate to vue 3" #1323 ), which bumped @nextcloud/vue from ^8.33.0 to ^9.6.0. That commit correctly converted :checked.sync to v-model but left the separate @update:checked="saveConfig" listeners unchanged. On @nextcloud/vue 8.x the component emitted update:checked, so both the binding and the save handler fired; on 9.x only update:modelValue is emitted. The same commit already used the correct event for NcSettingsSelectGroup (@update:modelValue="onSelectGroups"), so only the NcCheckboxRadioSwitch listeners were missed.

Affected: 4.7.0 through 4.7.5 and current main. Not affected: 4.6.x and earlier (Vue 2 / @nextcloud/vue 8). A backport to the 4.7 line is therefore needed in addition to main.

Fix

Replace @update:checked with @update:modelValue on all five NcCheckboxRadioSwitch switches (the four saveConfig switches and the group-restriction toggle).

Testing

Built against the released v4.7.5 and deployed to a live instance:

• Toggling any switch now persists and survives a reload.
• A PUT /apps/guests/config is now sent on toggle (previously only GET appeared in the access log).
• The "Your settings have been updated" toast shows.
• The group-restriction switch can now be toggled.

Fixes #995

🤖 AI (if applicable)

• The content of this PR was partly or fully generated using AI

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