Complete netdemo feature as a single commit on implant2.
See svdemo.txt for full documentation.
Recording: svdemo_record, delta compression, keyframes, auto-record,
chat capture, configstring tracking, map_restart handling.
Playback: svdemo_play, free camera (client-owned), follow mode,
pause, seek/seekexact with keyframes, scoreboard, PVS via usercmd
origin, SNAPFLAG_RESET_ENTITIES for clean transitions.
Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>
