cortex-agent client v2026.9.15

Highlights

• Version parity with server v2026.9.15. No functional change to the client.

Changes

• The client tree is byte-identical to client-v2026.9.14 — this tag exists so the published
  version matches the server it talks to.
• Fixes in this cycle that affect remote devices are all on the server side of the link:
  a POSIX reverse tunnel's remote port is now reclaimed instead of being retried into for the
  full ~15-minute TCP retransmission timeout, and the Windows eviction clears every stale
  sshd on a tunnel port rather than one, without touching a listener that is not sshd.
  A device on 2026.9.14 gets both the moment its server is updated.
• Nothing here needs a device update. Update for the version number, or don't.