Move broadcast message parsing logic from profiler/src/main.cpp into
server/TracyBroadcast.cpp/hpp. This reduces code duplication and enables
reuse by other tools (e.g., multi-capture).
ParseBroadcastMessage() handles all broadcast protocol versions (0-3) and
returns std::optional<BroadcastMessage>. ClientUniqueID() generates a unique
identifier from IP address and port.
Co-authored-by: Grégoire Roussel <gregoire.roussel@wandercraft.eu>
