Adds an OFF-by-default profile that dependency:unpacks the libtorch native runtime
(org.pytorch:libtorch-cxx11-cu128:2.7.1:zip, cu128) from mirror.elphel.com/maven-dependencies
into target/libtorch-dist for the native DNN backend (libtpdnn.so / CuasDnnLocal) on a
deployment box. The default build never downloads the 3.8GB zip.

Artifact published to the mirror in maven layout (server-side copy of the existing zip)
via tile_processor_gpu/jna/publish_libtorch_mirror.sh. Verified: zip + .pom reachable at
the computed maven URL (HTTP 200, 3.78GB), profile parses (mvn -Plibtorch validate OK).
Full unpack deferred (redundant on this box - libtorch already extracted); exercises on
first deployment machine via `mvn -Plibtorch generate-resources`.
Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>