Installation management

[igor-sirotin]

Owner: Chat Team

Extracted from #346 (Add Group Chat): the installation (device) lifecycle for accounts. The current implementation registers installation keys and key packages, but installations cannot yet be listed, removed, or revoked, and known gaps prevent true multi-device usage.

Feature: Group Chat

FURPS:

• F1. Accounts can receive a message in multiple locations (e.g. devices) by registering new installations.
• F2. Accounts can view and remove installations as needed.
• F5. Account can view all provisioned installations.
• F6. Account can revoke other installations in case of a lost device.
• +PRIV2. No identifying information is visible when registering an installation — to be addressed by design in the key package registry replacement (Testnet KeyPackage Registry libchat#110 is an interim testnet service).

Roadmap: https://roadmap.logos.co/messaging/roadmap/milestones/2026-chat-beta