fix: stop forcing players to T on UI reset, which restarted the round (#10)

[cmer81]

Root cause

FixClientUI() (called on any non-infection death of a player in thirdperson/mirror, e.g. sm_spec with forced suicide, kill, fall damage) moved the player to spectator and then always to T when ZombieReloaded is loaded.
Before the mother zombie spawns every player is CT, so this created the first spawnable T. CS:S CCSGameRules::NeededPlayersCheck then sees both teams populated after one was empty and calls TerminateRound(3.0, Game_Commencing), restarting the round. Neither ZR nor TeamManager (outside warmup) block that reason.

Fix

• FixClientUI() puts the player back in their original team instead of forcing T (ZR already moves T spawns to CT and its respawn timer accepts both teams). No-op if the player is not on T/CT.
• The delayed respawn now uses the userid and skips players that are alive or were moved to spectator meanwhile.
• Remove the "no zombie spawned" restriction on sm_tp/sm_mirror added in feat: bump to 1.3.1 #9 as a workaround, and its now-unused state (g_bZombieSpawned, g_bTeamManager, round_start hook, ZR_OnClientInfected).
• Bump version to 1.3.7.

Verification

Compiled with spcomp 1.13.0.7427, no errors/warnings.

Closes #10