v0.4.6

Fixed

• A node that reconnected over a half-open link (the old TCP connection never
  sent a FIN, common on Windows) was silently dropped from the routable set even
  though its new connection was alive. The hub keyed a node only by its stable id
  and removed every entry with that id, so when the dead-peer timer reaped the
  stale duplicate connection (~75s after the node had already reconnected) it
  evicted the live reconnected entry too. The node stayed "ghost-connected" (TCP
  up, replying to pings) but invisible on the dashboard and carrying no traffic
  until a restart. Each connection now carries a unique sequence: a reconnect
  displaces the old entry on enroll, and the stale reap removes only its own
  connection, never the live one. Hub-only fix, no protocol change.

Added

• Windows nodes support opt-in --auto-update. The running .exe is locked, so
  a detached PowerShell helper waits for the node process to exit, then re-runs
  install.ps1 to swap the binary and restart the service. Off by default, like
  the unix path; install.ps1 gained an -AutoUpdate switch and the dashboard
  auto-update toggle now applies to the Windows install command too.
• CI gained an MSRV (Rust 1.74) build job and a cargo audit job, so the
  declared minimum toolchain and dependency advisories are both enforced.