Remove spectatorClientNum hack

spectatorClientNum was hardcoded to MAX_CLIENTS-1 but the spectator
actually connected at a different slot. All skip checks using it
were no-ops protecting the wrong slot. Removed entirely:

- Zombie slots handle player slot reservation
- G_RunFrame recreates the spectator entity via ClientThink_real
- PlayerState injection writes all slots (spectator's ps gets
  overwritten by ClientThink_real anyway)
- SVD_SpectatorClientNum accessor removed

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

code/server/server.h

@@ -357,7 +357,6 @@ void		SVD_Stop_f( void );
 qboolean	SVD_PlaybackFrame( void );
 qboolean	SVD_IsRecording( void );
 qboolean	SVD_IsPlaying( void );
-int			SVD_SpectatorClientNum( void );
 
 //============================================================
 //

code/server/sv_netdemo.c

@@ -102,7 +102,8 @@ typedef struct {
 	int				playFps;			// original sv_fps
 	char			*savedConfigstrings[MAX_CONFIGSTRINGS]; // from demo header, re-applied after map load
 	char			playMapName[SVDEMO_MAX_MAPNAME];
-	int				spectatorClientNum;	// which client slot is the demo spectator
+	// spectatorClientNum removed — zombie slots handle reservation,
+	// and G_RunFrame recreates the spectator entity each frame.
 	int				nextFrameTime;		// serverTime of next frame to read
 	qboolean		endOfDemo;
 	qboolean		needConfigstrings;	// apply saved configstrings on first frame
@@ -686,11 +687,8 @@ static qboolean SVD_ReadFrame( fileHandle_t f ) {
 	MSG_Init( &msg, msgBuf, sizeof(msgBuf) );
 	msg.cursize = blockLen;
 
-	// clear all non-spectator entities
+	// clear all entities (spectator's entity is recreated by ClientThink_real)
 	for ( i = 0; i < sv.num_entities; i++ ) {
-		if ( i == demo.spectatorClientNum ) {
-			continue;
-		}
 		ent = SV_GentityNum( i );
 		if ( ent->r.linked ) {
 			SV_UnlinkEntity( ent );
@@ -750,11 +748,6 @@ static qboolean SVD_ReadFrame( fileHandle_t f ) {
 		demo.playPrevEntities[entNum].es = newEs;
 		demo.playPrevEntities[entNum].active = qtrue;
 
-		// skip the spectator's slot
-		if ( entNum == demo.spectatorClientNum ) {
-			continue;
-		}
-
 		// apply to server entity
 		ent = SV_GentityNum( entNum );
 		ent->s = newEs;
@@ -774,11 +767,6 @@ static qboolean SVD_ReadFrame( fileHandle_t f ) {
 		}
 	}
 
-	// ensure spectator slot is counted
-	if ( demo.spectatorClientNum + 1 > sv.num_entities ) {
-		sv.num_entities = demo.spectatorClientNum + 1;
-	}
-
 	// read player states (delta compressed)
 	{
 		msg_t psmsg;
@@ -818,14 +806,14 @@ static qboolean SVD_ReadFrame( fileHandle_t f ) {
 					demo.playPrevPlayers[clientNum].active = qtrue;
 
 					// inject into game module's client state
-					if ( clientNum != demo.spectatorClientNum ) {
+					{
 						playerState_t *gamePs = SV_GameClientNum( clientNum );
 						*gamePs = newPs;
 					}
 				} else {
 					demo.playPrevPlayers[clientNum].active = qfalse;
 					// clear game playerState so G_RunFrame sees commandTime=0
-					if ( clientNum != demo.spectatorClientNum ) {
+					{
 						playerState_t *gamePs = SV_GameClientNum( clientNum );
 						Com_Memset( gamePs, 0, sizeof(*gamePs) );
 					}
@@ -906,9 +894,6 @@ void SVD_Play_f( void ) {
 	demo.playing = qtrue;
 	demo.endOfDemo = qfalse;
 
-	// The spectator gets the highest slot: MAX_CLIENTS - 1
-	demo.spectatorClientNum = MAX_CLIENTS - 1;
-
 	Com_Printf( "Playing server demo: map=%s maxclients=%d fps=%d\n",
 		demo.playMapName, demo.playMaxClients, demo.playFps );
 
@@ -1032,6 +1017,3 @@ qboolean SVD_IsPlaying( void ) {
 	return demo.playing;
 }
 
-int SVD_SpectatorClientNum( void ) {
-	return demo.spectatorClientNum;
-}