fix: reset player cache on prestige

Tests/QuestiePlayerPrestigeReset_spec.lua

@@ -0,0 +1,40 @@
+describe("QuestiePlayer prestige reset", function()
+    local resetCalls
+
+    before_each(function()
+        dofile("Tests/wow_api_mock.lua")
+
+        resetCalls = 0
+        QuestieQuest.SmoothReset = function()
+            resetCalls = resetCalls + 1
+        end
+
+        dofile("Modules/QuestiePlayer.lua")
+        QuestiePlayer.private.playerLevel = 70
+    end)
+
+    it("drops the cached level to 1 and refreshes quest state when prestige restarts", function()
+        _G.UnitLevel = function()
+            return 1
+        end
+
+        local resetTriggered = QuestiePlayer:SetPlayerLevel(1)
+
+        assert.is_true(resetTriggered)
+        assert.equals(1, QuestiePlayer.private.playerLevel)
+        assert.equals(1, resetCalls)
+    end)
+
+    it("does not treat an ordinary level 1 login as a prestige reset", function()
+        QuestiePlayer.private.playerLevel = 1
+        _G.UnitLevel = function()
+            return 1
+        end
+
+        local resetTriggered = QuestiePlayer:SetPlayerLevel(1)
+
+        assert.is_false(resetTriggered)
+        assert.equals(1, QuestiePlayer.private.playerLevel)
+        assert.equals(0, resetCalls)
+    end)
+end)