D321: map the D318 trigger chain (tanks -> chr 254 gas cascade -> combat bit, ~3.5s authored delay; derail same-tick; PC faithful to N64) + GE_OBJT probe extensions (AI-list ID, GAS prop timestamps)

src/game/propobj.c

@@ -9427,6 +9427,24 @@ apply_damage:
     {
         if (objGetDestroyedLevel(obj) == 1)
         {
+#ifdef PORT
+            /* D318-followup (diagnosis only, GE_OBJT=1): timestamp each
+             * GAS_RELEASING prop destruction so the tank-blow tick is
+             * correlatable against the OBJT stage-flag writes. Read-only,
+             * capped, no behavior change; N64 build unaffected. */
+            extern char *getenv(const char *);
+            static int s_gas = -1;
+            static int s_gasn = 0;
+
+            if (s_gas < 0) { s_gas = getenv("GE_OBJT") != NULL; }
+            if (s_gas && (s_gasn < 200))
+            {
+                osSyncPrintf("OBJT: t=%d GAS prop destroyed at (%.0f,%.0f,%.0f) [gas effect armed]\n",
+                             (int)g_GlobalTimer, (double)obj->runtime_pos.x,
+                             (double)obj->runtime_pos.y, (double)obj->runtime_pos.z);
+                s_gasn++;
+            }
+#endif
             init_trigger_toxic_gas_effect(&obj->runtime_pos);
         }
     }