feat(settings): add a button to revoke all other sessions

[pringelmann]

Summary

Adds a "Revoke all other sessions" button that revokes every credential on the account except the current session.

Kooha-2026-08-24-18-49-03.webm

Behaviour

• Tokens marked for remote wipe are skipped. Revoking one cancels its pending wipe, which is already its own separately worded confirmation with its own activity subject.
• Revocations produce a single activity entry with a count, not one per token.
• The current session survives, and the confirmation dialog states how many devices lose access.

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)

AI (if applicable)

• The content of this PR was partly or fully generated using AI (unit & E2E tests, reviewed by me)