ConnectOptions previously took tsclientlib's default Version. Servers that
strictly check the announced client signature could refuse or downgrade
those sessions. Add pick_client_version() that selects a stable signed
descriptor matching the runtime OS:
Windows -> Version::Windows_5_0_0_beta51
Linux -> Version::Linux_5_0_0_beta51
macOS -> Version::macOS_5_0_0_beta51
Android -> Version::Android_3_5_0__7
iOS -> Version::iOS_3_5_6
other -> Linux fallback
All five variants are guaranteed to exist in the vendored tsproto-types
enum at compile time; build fails loudly if upstream removes one.
Wired into Connection::build(...).version(pick_client_version()) on every
connect. Emits 'selected TS3 client_version' info log line so the choice
is visible in chanora.log.
EdisonJwa
8acd456af1