TBTR: Fix various refit issues in refit as incoming vehicle mode

Allow refits to fail in refit as incoming vehicle mode
Remove virtual train mode from CmdRefitVehicle
Fix refit as incoming for non-head parts being free

src/train_cmd.cpp

@@ -7221,6 +7221,11 @@ CommandCost CmdTemplateReplaceVehicle(TileIndex tile, DoCommandFlag flags, uint3
 
 	CommandCost buy(EXPENSES_NEW_VEHICLES);
 
+	auto refit_unit = [&](const Train *unit, CargoID cid, uint16 csubt) {
+		CommandCost refit_cost = DoCommand(unit->tile, unit->index, cid | csubt << 8 | (1 << 16), flags, GetCmdRefitVeh(unit));
+		if (refit_cost.Succeeded()) buy.AddCost(refit_cost);
+	};
+
 	if (need_replacement) {
 		// step 1: generate primary for newchain and generate remainder_chain
 		// 1. primary of incoming might already fit the template
@@ -7292,7 +7297,7 @@ CommandCost CmdTemplateReplaceVehicle(TileIndex tile, DoCommandFlag flags, uint3
 			// additionally, if we don't want to use the template refit, refit as incoming
 			// the template refit will be set further down, if we use it at all
 			if (!refit_to_template) {
-				buy.AddCost(DoCommand(new_chain->tile, new_chain->index, store_refit_ct | store_refit_csubt << 8 | (1 << 16) | (1 << 31), flags, GetCmdRefitVeh(new_chain)));
+				refit_unit(new_chain, store_refit_ct, store_refit_csubt);
 			}
 		}
 
@@ -7350,15 +7355,10 @@ CommandCost CmdTemplateReplaceVehicle(TileIndex tile, DoCommandFlag flags, uint3
 			if (new_part != nullptr) {
 				last_veh = new_part;
 			}
-			// TODO: is this enough ? might it be that we bought a new wagon here and it now has std refit ?
-			if (need_refit && new_part != nullptr) {
-				if (refit_to_template) {
-					DoCommand(tile, new_part->index, cur_tmpl->cargo_type | (cur_tmpl->cargo_subtype << 8) | (1 << 16) | (1 << 31), flags, GetCmdRefitVeh(new_part));
-				} else {
-					DoCommand(tile, new_part->index, store_refit_ct | (store_refit_csubt << 8) | (1 << 16) | (1 << 31), flags, GetCmdRefitVeh(new_part));
-				}
-			}
 
+			if (!refit_to_template && new_part != nullptr) {
+				refit_unit(new_part, store_refit_ct, store_refit_csubt);
+			}
 		}
 	} else {
 		/* no replacement done */

src/vehicle_cmd.cpp

@@ -512,7 +512,6 @@ static CommandCost RefitVehicle(Vehicle *v, bool only_this, uint8 num_vehicles,
  *                      Only used if "refit only this vehicle" is false.
  * - p2 = (bit 24)     - Automatic refitting.
  * - p2 = (bit 25)     - Refit only this vehicle. Used only for cloning vehicles.
- * - p2 = (bit 31)     - Is a virtual train (used by template replacement to allow refitting without stopped-in-depot checks)
  * @param text unused
  * @return the cost of this operation or an error
  */
@@ -529,10 +528,9 @@ CommandCost CmdRefitVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint
 
 	bool auto_refit = HasBit(p2, 24);
 	bool is_virtual_train = v->type == VEH_TRAIN && Train::From(front)->IsVirtual();
-	bool virtual_train_mode = HasBit(p2, 31) || is_virtual_train;
 	bool free_wagon = v->type == VEH_TRAIN && Train::From(front)->IsFreeWagon(); // used by autoreplace/renew
 
-	if (virtual_train_mode) {
+	if (is_virtual_train) {
 		CommandCost ret = CheckOwnership(front->owner);
 		if (ret.Failed()) return ret;
 	} else {
@@ -544,7 +542,7 @@ CommandCost CmdRefitVehicle(TileIndex tile, DoCommandFlag flags, uint32 p1, uint
 	if (v != front && (v->type == VEH_AIRCRAFT)) return CMD_ERROR;
 
 	/* Allow auto-refitting only during loading and normal refitting only in a depot. */
-	if (!virtual_train_mode) {
+	if (!is_virtual_train) {
 		if ((flags & DC_QUERY_COST) == 0 && // used by the refit GUI, including the order refit GUI.
 				!free_wagon && // used by autoreplace/renew
 				(!auto_refit || !front->current_order.IsType(OT_LOADING)) && // refit inside stations