Gaoxy v0.5.5

Gaoxy 0.5.5

Gaoxy now uses the published Hex package abyss == 0.9.0 in place of the Git
revision 9b710e6480900e16e304f40e63623aff8c922e19 (Abyss 0.7.0).
The coordinated upstream release publishes abyss and abyss_raw 0.9.0 from
tag 0.9.0, commit f336d939ff8a23b38c66072f1d1ba5873b5ef43b.
Gaoxy uses only core abyss; ordinary services do not install abyss_raw,
the old bundled DHCP NIF or its Rustler build dependency.

Hex package staging preserves the selected Abyss requirement and rejects the
obsolete Git dependency. All three tracked locks are resolved against the
published core package. Hell and HTTP/TLS/QUIC versions are unchanged.
UDP, lifecycle and optional QUIC behavior retain the existing public adapters.

This patch changes dependency packaging and build requirements. It adds no
protocol features or deployment/production qualification. See the
migration acceptance record for source,
dependency-boundary checks, executed gates and publication status.