Introduce a second match mode alongside Classic. In Conversion mode
hiders are invisible to each other (and to hunters during Hide), and a
hunter hit converts the hider into a full hunter in place instead of
sending them to the spectator freecam. The mode is replicated to all
clients through the existing phase named-message byte; visibility is
computed locally per client per mode.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>