o Major bugfixes (security):
    - Negotiate CGO cryptography with every hop that supports it.
      Previously, we failed to negotiate CGO with hops other
      than the final hop of a circuit, since we did not enable
      congestion-control with those hops.  Now, we negotiate
      congestion-control _and_ CGO whenever we can.
      Fixes bug 41348; bugfix on 0.4.9.3-alpha.
      Tracked as TROVE-2026-033.