fix(quickbuild): take precondition items when the build starts, give them back on cancel

A quickbuild's HasItem preconditions took their items only when the build
completed and never gave them back. Live took them when the build started
and gave them back when it was cancelled: the FV Stone Warrior pedestal
(LOT 8551, precondition 99: 5 of LOT 6194) took the items at Building 5
times and added them back with the loot source Quickbuild on each of the 3
cancels in the live captures.

Preconditions now report their item costs instead of removing items while
checking. A quickbuild takes them at the start, gives them back on cancel
or a reset during the build, keeps them on completion, and gives them back
when the builder leaves the world mid-build.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

tests/dGameTests/CMakeLists.txt

@@ -23,6 +23,7 @@ set(DGAMETEST_SOURCES
 	"SetCurrencySourceTests.cpp"
 	"LootDropPositionTests.cpp"
 	"LootActivityCoinsTests.cpp"
+	"PreconditionItemCostTests.cpp"
 	"SpiderQueenTests.cpp"
 	"TacArcTests.cpp"
 )

tests/dGameTests/PreconditionItemCostTests.cpp

@@ -0,0 +1,32 @@
+#include "Preconditions.h"
+
+#include <map>
+
+#include <gtest/gtest.h>
+
+// The items a quickbuild's HasItem precondition takes when the build starts
+// (the FV Stone Warrior pedestal: precondition 99, 5 of LOT 6194).
+
+namespace {
+	std::function<uint32_t(LOT)> Holding(const std::map<LOT, uint32_t>& inventory) {
+		return [inventory](const LOT lot) {
+			const auto it = inventory.find(lot);
+			return it == inventory.end() ? 0u : it->second;
+		};
+	}
+}
+
+TEST(PreconditionItemCostTests, TakesTheCountOfTheHeldLot) {
+	EXPECT_EQ(Precondition::PickItemCost({ 6194 }, 5, Holding({ { 6194, 7 } })), (ItemCost{ 6194, 5 }));
+	EXPECT_EQ(Precondition::PickItemCost({ 6194 }, 5, Holding({ { 6194, 5 } })), (ItemCost{ 6194, 5 }));
+}
+
+TEST(PreconditionItemCostTests, NotEnoughTakesNothing) {
+	EXPECT_FALSE(Precondition::PickItemCost({ 6194 }, 5, Holding({ { 6194, 4 } })));
+	EXPECT_FALSE(Precondition::PickItemCost({ 6194 }, 5, Holding({})));
+}
+
+// A precondition that lists several LOTs is met by any of them: the first one held is taken
+TEST(PreconditionItemCostTests, TakesTheFirstHeldOfSeveralLots) {
+	EXPECT_EQ(Precondition::PickItemCost({ 100, 200, 300 }, 2, Holding({ { 100, 1 }, { 200, 2 }, { 300, 9 } })), (ItemCost{ 200, 2 }));
+}