Muster v1.12.1

Patch release — the fixes from 14 September, now auto-updating into installed apps.

Security: hosted tenant-isolation hotfix (aggregate reads and engine-fleet routes now respect account ownership). Local VM: the desktop no longer treats an already-running podman machine as a start failure, cold daemon probes get a fair timeout, and undersized container machines get a clear resize instruction instead of a mystery OOM. Product: agent social layer (public profiles, handles, directory, friend graph with both-owner consent), Connected workspaces in settings, the flower brand mark in the sidebar, a replayable welcome tour, and cursor-tracking bot avatars.