Fix up ExploreService APIs and add unit tests

tests/Helpers/StaminaHelperTests.cs

@@ -0,0 +1,42 @@
+using MariesWonderland.Data;
+using MariesWonderland.Helpers;
+using MariesWonderland.Models.Entities;
+
+namespace MariesWonderland.Tests.Helpers;
+
+public class StaminaHelperTests
+{
+    private static GameConfig ConfigWithCap(int cap) => new() { StaminaMaxCount = cap };
+
+    [Fact]
+    public void AddStamina_BelowCap_AddsFullAmount()
+    {
+        var status = new EntityIUserStatus { StaminaMilliValue = 0 };
+
+        StaminaHelper.AddStamina(status, 50, ConfigWithCap(999), nowMs: 1000L);
+
+        Assert.Equal(50_000, status.StaminaMilliValue);
+        Assert.Equal(1000L, status.StaminaUpdateDatetime);
+    }
+
+    [Fact]
+    public void AddStamina_ExceedsCap_ClampsToMax()
+    {
+        // Start near cap (990 stamina), add 50 → should clamp to 999
+        var status = new EntityIUserStatus { StaminaMilliValue = 990_000 };
+
+        StaminaHelper.AddStamina(status, 50, ConfigWithCap(999), nowMs: 2000L);
+
+        Assert.Equal(999_000, status.StaminaMilliValue);
+    }
+
+    [Fact]
+    public void AddStamina_AlreadyAtCap_DoesNotExceed()
+    {
+        var status = new EntityIUserStatus { StaminaMilliValue = 999_000 };
+
+        StaminaHelper.AddStamina(status, 50, ConfigWithCap(999), nowMs: 3000L);
+
+        Assert.Equal(999_000, status.StaminaMilliValue);
+    }
+}