Launch pend counter: no timeout, no queue entry (mid-load launch crash 2)

The take-1 deferral (re-post at +1s, capped at 120) turned a SLOW load
into a crash: loads on a busy operator box measure 1-2+ minutes, the
cap expired, and the original "Not ready to run" Fail/abort fired
(field report: sound after ~1 min, crash ~2 min later; the log shows
exactly 120 deferrals all in LoadingMission).

A mid-load RunMission now just bumps gBTRunMissionPendCount -- nothing
enters the event queue and there is NO timeout to outlive -- and
CheckLoadMessageHandler drains the counter immediately after advancing
LoadingMission -> WaitingForLaunch, re-posting that many stack
RunMissionMessages (the engine's own no-console launch pattern at the
same site, which also demonstrates Post spools stack messages safely).

Verified (two-round rig, round 1): both relay launches pended through
the load, fired at load completion, the requested mech spawned and the
scene went live.  Round reset + round-2 rejoin remain verified from the
prior run; why loads take 1-2+ min on a busy box is left as an open
perf question.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

engine/MUNGA/APP.cpp

@@ -1415,6 +1415,18 @@ void
 				Post(DefaultEventPriority, this, &run_mission_message);
 				Tell("Sent ready message to ourselves\n");
 			}
+
+			{
+				// relay launches that arrived MID-LOAD fire now (they could
+				// not enter the queue then -- see L4APP.cpp pend counter)
+				extern int BTTakePendingRunMissions(void);
+				int pended_launches = BTTakePendingRunMissions();
+				while (pended_launches-- > 0)
+				{
+					RunMissionMessage pended_run;
+					Post(DefaultEventPriority, this, &pended_run);
+				}
+			}
 		}
 
 		//