Extract the TLS-without-CA guard into a shared `build_tls_config` helper
in options.rs so both GatewayClient and GalaxyClient use identical logic.
GalaxyClient previously had no guard, so TLS-without-CA produced a cryptic
tonic handshake failure; it now returns the same actionable InvalidEndpoint
error. The guard message notes that a server-name override affects SNI but
does not pin trust. Add --require-certificate-validation to ConnectionArgs
in the CLI binary. Add a mirror test for GalaxyClient in tests/tls.rs.
Joseph Doherty
cdfad420bb