Diag: BT_JAM_LOG (per-shot weapon temp/jam roll) + BT_VALVE (force condenser detent)

Probes for verifying the autocannon jam/coolant mechanic against QA ground-truth
(AFCs jam on ~3rd shot uncooled). BT_JAM_LOG logs currentTemp/degradT/failT/alarm/p
at each fire attempt; BT_VALVE=<n> forces every condenser valveState so cooling can
be tested at a known level. No behavior change (both gated on env).

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

game/reconstructed/projweap.cpp

@@ -517,6 +517,16 @@ void
 Logical
 	ProjectileWeapon::CheckForJam()
 {
+	if (getenv("BT_JAM_LOG"))
+		DEBUG_STREAM << "[jam] " << GetName()
+			<< " T=" << currentTemperature
+			<< " degT=" << degradationTemperature
+			<< " failT=" << failureTemperature
+			<< " alarm=" << (int)heatAlarm.GetLevel()
+			<< " liveFire=" << (int)LiveFireEnabled()
+			<< " p=" << ((_DAT_004bc064 * currentTemperature) / failureTemperature)
+			<< "\n" << std::flush;
+
 	if (!LiveFireEnabled())										// *(*(this+0xd0)+400)+0x25c
 		return False;