v0.32.0

Added

• synapse hub --max-clients N and --max-msg-kb K cap concurrent connections and
  inbound frame size, so one host or one oversized message cannot exhaust the hub.
• synapse health probes a hub (exit 0 reachable, 1 not), wired as a Docker HEALTHCHECK.
• The hub token can be supplied with --token-file PATH or the SYNAPSE_TOKEN
  environment variable instead of --token, which is visible in the process list.

Changed

• The hub drains on SIGTERM/SIGINT (graceful shutdown) instead of running on a bare
  future; a name is protected from an eviction storm by a takeover cooldown.
• The Docker image is pinned to python:3.13-slim, the highest version CI exercises.

Security

• SECURITY.md documents the advisory file-scope model (the hub never reads the
  filesystem, so claim paths are not a traversal surface), the new caps, and that
  state is plaintext at rest on the local machine.