THRALL v0.4.1 — Tool for Hierarchical Replication And Identity Linking

Patch release: the thrall-syncthing peer image now declares /var/syncthing as a volume, so Syncthing can create its XDG dirs (~/.local) under the hardened --read-only Quadlet runtime. Without it, the peer node crashed on startup with mkdir /var/syncthing/.local: read-only file system. The persistent index database and config remain in the bind-mounted /var/syncthing/config.