refactor(sonar): clean up issues reported on PR 209

- remove locals left unused after the dead-store cleanup (cpp:S1481, cpp:S1854)
- unnamed unused parameter (cpp:S1172)
- single-use declarations moved into if init-statements (cpp:S6004)
- auto for casted initialisers (cpp:S5827)
- const references and pointers where nothing is modified (cpp:S5350)
- rename structured bindings shadowed by inner declarations (cpp:S1117)

world/EvLaunch.cpp

@@ -163,7 +163,7 @@ bool TEventLauncher::check_activation_key() const {
 
 	bool result = Console::Pressed(key);
 
-	char modifier = static_cast<char>(iKey >> 8);
+	auto modifier = static_cast<char>(iKey >> 8);
 	if (modifier & GLFW_MOD_SHIFT)
 		result &= Global.shiftState;
 	if (modifier & GLFW_MOD_CONTROL)

world/Traction.cpp

@@ -416,7 +416,7 @@ void TTraction::ResistanceCalc(int d, double r, TTractionPowerSource *ps)
     if (d >= 0)
     { // podążanie we wskazanym kierunku
         TTraction *t = hvNext[d];
-        TTraction *p;
+        TTraction const *p;
         if (ps)
             psPower[d ^ 1] = ps; // podłączenie podanego
         else

world/mtable.cpp

@@ -227,7 +227,7 @@ void TTrainParameters::NewName(std::string_view NewTrainName)
     LocLoad = 0;
 }
 
-void TTrainParameters::UpdateVelocity(int Stationcount, double vActual)
+void TTrainParameters::UpdateVelocity(int /*Stationcount*/, double vActual)
 // zapisywanie prędkości maksymalnej do wcześniejszych odcinków
 // wywoływane z numerem ostatniego przetworzonego przystanku
 {