fix(loot): activity reward coins use the reward's ChallengeRating level

ActivityRewards coins were always read from CurrencyTable npcminlevel 1.
Live used the reward row's ChallengeRating as the npcminlevel, and level 1
when the currency index has no row for that level:
- FV foot races (ChallengeRating 4, index 1) gave 36 and 48 coins, which
  only level 4 (30-50) fits; level 1 is 3-5.
- Frakjaw's chest (activity 58, ChallengeRating 6) gave 250 each to a team
  of 2: its currency indices 123-126 only have a level 6 row (500), so DLU
  gave nothing.
- Quickbuilds, wishing wells and chests have ChallengeRating 1; survival
  and the shooting galleries have ratings with no row and keep level 1.

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

tests/dGameTests/CMakeLists.txt

@@ -22,6 +22,7 @@ set(DGAMETEST_SOURCES
 	"HolidayEventsTests.cpp"
 	"SetCurrencySourceTests.cpp"
 	"LootDropPositionTests.cpp"
+	"LootActivityCoinsTests.cpp"
 	"SpiderQueenTests.cpp"
 	"TacArcTests.cpp"
 )

tests/dGameTests/LootActivityCoinsTests.cpp

@@ -0,0 +1,44 @@
+#include "Loot.h"
+#include "CDCurrencyTableTable.h"
+
+#include <gtest/gtest.h>
+
+// ActivityRewards coins: the reward's ChallengeRating is the CurrencyTable npcminlevel, level 1 when that level has
+// no row, as live rolled them.
+
+namespace {
+	CDCurrencyTable Row(const uint32_t index, const uint32_t level, const uint32_t min, const uint32_t max) {
+		return CDCurrencyTable{ .currencyIndex = index, .npcminlevel = level, .minvalue = min, .maxvalue = max, .id = 0 };
+	}
+
+	// CurrencyTable index 1 as the client data has it
+	const std::vector<CDCurrencyTable> index1 = { Row(1, 1, 3, 5), Row(1, 2, 5, 9), Row(1, 3, 9, 15), Row(1, 4, 30, 50), Row(1, 5, 60, 100) };
+}
+
+// FV foot races (ChallengeRating 4): live gave 36 and 48 coins, which only level 4 (30-50) fits
+TEST(LootActivityCoinsTests, ChallengeRatingPicksTheLevel) {
+	EXPECT_EQ(Loot::GetActivityCoinRange(index1, 4), std::make_pair(30u, 50u));
+}
+
+// Quickbuilds, wishing wells and chests (ChallengeRating 1)
+TEST(LootActivityCoinsTests, ChallengeRatingOneIsLevelOne) {
+	EXPECT_EQ(Loot::GetActivityCoinRange(index1, 1), std::make_pair(3u, 5u));
+}
+
+// Survival and shooting galleries: their ChallengeRating has no row, so level 1 is used
+TEST(LootActivityCoinsTests, MissingLevelFallsBackToLevelOne) {
+	EXPECT_EQ(Loot::GetActivityCoinRange(index1, 7), std::make_pair(3u, 5u));
+	EXPECT_EQ(Loot::GetActivityCoinRange(index1, 0), std::make_pair(3u, 5u));
+}
+
+// Frakjaw's chest (activity 58, ChallengeRating 6): index 125 has only a level 6 row of 500, which live split
+// between a team of 2
+TEST(LootActivityCoinsTests, IndexWithOnlyTheChallengeLevel) {
+	const std::vector<CDCurrencyTable> index125 = { Row(125, 6, 500, 500) };
+	EXPECT_EQ(Loot::GetActivityCoinRange(index125, 6), std::make_pair(500u, 500u));
+	EXPECT_EQ(Loot::GetActivityCoinRange(index125, 2), std::make_pair(0u, 0u));
+}
+
+TEST(LootActivityCoinsTests, NoRowsNoCoins) {
+	EXPECT_EQ(Loot::GetActivityCoinRange(std::vector<CDCurrencyTable>{}, 1), std::make_pair(0u, 0u));
+}