fix: leave MMOCore class skill casts alone

src/main/java/net/tfminecraft/magic/integration/SkillIdResolver.java

@@ -37,6 +37,14 @@ public static boolean isActiveCast(Skill cast) {
         return lower != null && Cache.castTriggers.contains(lower.toUpperCase(Locale.ROOT));
     }
 
+    /**
+     * True for a skill cast from an MMOCore class skill bar. Class skills are not runes:
+     * Magic leaves them alone (no refusal, whiff, weapon wear or cast drift).
+     */
+    public static boolean isClassCast(Skill cast) {
+        return cast instanceof CastableSkill;
+    }
+
     /**
      * Spells come from MMOItems key combinations, whose {@code AbilityData} is a plain
      * MythicLib {@link Skill} and never an MMOCore {@link CastableSkill}. The handler id

src/main/java/net/tfminecraft/magic/listener/CastDriftListener.java

@@ -23,7 +23,7 @@ public void onSkillCast(SkillCastEvent event) {
             return;
         }
         Skill cast = event.getCast();
-        if (!SkillIdResolver.isActiveCast(cast)) {
+        if (!SkillIdResolver.isActiveCast(cast) || SkillIdResolver.isClassCast(cast)) {
             return;
         }
         Player player = event.getPlayer();

src/main/java/net/tfminecraft/magic/listener/ResonanceCastListener.java

@@ -65,7 +65,7 @@ public void onPlayerCastSkill(PlayerCastSkillEvent event) {
             return;
         }
         Skill cast = event.getCast();
-        if (!SkillIdResolver.isActiveCast(cast)) {
+        if (!SkillIdResolver.isActiveCast(cast) || SkillIdResolver.isClassCast(cast)) {
             return;
         }
         String skillId = SkillIdResolver.resolveSkillId(cast);

src/test/java/net/tfminecraft/magic/ClassCastSkipTest.java

@@ -0,0 +1,83 @@
+package net.tfminecraft.magic;
+
+import static org.junit.jupiter.api.Assertions.*;
+import static org.mockito.Mockito.*;
+
+import io.lumine.mythic.lib.api.event.skill.PlayerCastSkillEvent;
+import io.lumine.mythic.lib.api.event.skill.SkillCastEvent;
+import io.lumine.mythic.lib.skill.Skill;
+import io.lumine.mythic.lib.skill.trigger.TriggerType;
+import net.Indyuce.mmocore.skill.CastableSkill;
+import net.tfminecraft.magic.gear.GearHand;
+import net.tfminecraft.magic.integration.SkillIdResolver;
+import net.tfminecraft.magic.listener.CastDriftListener;
+import net.tfminecraft.magic.listener.ResonanceCastListener;
+import net.tfminecraft.magic.registry.SkillElementRegistry;
+import net.tfminecraft.magic.session.ResonanceSessionManager;
+import org.junit.jupiter.api.*;
+import org.mockbukkit.mockbukkit.*;
+
+/** MMOCore class skills are cast from the skill bar, not from runes: Magic must not touch them. */
+class ClassCastSkipTest {
+  ServerMock server;
+
+  @BeforeEach
+  void setup() {
+    server = MockBukkit.mock();
+    Magic.plugin = mock(Magic.class, RETURNS_DEEP_STUBS);
+    SkillElementRegistry.clear();
+  }
+
+  @AfterEach
+  void cleanup() {
+    Magic.plugin = null;
+    SkillElementRegistry.clear();
+    MockBukkit.unmock();
+  }
+
+  @Test
+  void onlyMmocoreCastableSkillsCountAsClassCasts() {
+    assertTrue(SkillIdResolver.isClassCast(mock(CastableSkill.class)));
+    assertFalse(SkillIdResolver.isClassCast(mock(Skill.class)));
+    assertFalse(SkillIdResolver.isClassCast(null));
+  }
+
+  @Test
+  void resonanceGateIgnoresClassCastsEvenForBoundSpells() {
+    var listener = new ResonanceCastListener();
+    var event = mock(PlayerCastSkillEvent.class);
+    var cast = mock(CastableSkill.class);
+    when(event.getCast()).thenReturn(cast);
+    when(event.getPlayer()).thenReturn(server.addPlayer());
+    SkillElementRegistry.register("fire_shard", "oseni", 1);
+    try (var ids = mockStatic(SkillIdResolver.class);
+        var hand = mockStatic(GearHand.class)) {
+      ids.when(() -> SkillIdResolver.isActiveCast(cast)).thenReturn(true);
+      ids.when(() -> SkillIdResolver.isClassCast(cast)).thenReturn(true);
+      ids.when(() -> SkillIdResolver.resolveSkillId(cast)).thenReturn("fire_shard");
+      listener.onPlayerCastSkill(event);
+      ids.verify(() -> SkillIdResolver.resolveSkillId(cast), never());
+      hand.verifyNoInteractions();
+    }
+    verify(event, never()).setCancelled(anyBoolean());
+    verify(cast, never()).whenCast(any());
+  }
+
+  @Test
+  void castDriftIgnoresClassCasts() {
+    var listener = new CastDriftListener();
+    var event = mock(SkillCastEvent.class);
+    var cast = mock(CastableSkill.class);
+    when(cast.getTrigger()).thenReturn(TriggerType.CAST);
+    when(cast.getParameter("mana")).thenReturn(40.);
+    when(event.getCast()).thenReturn(cast);
+    var player = server.addPlayer();
+    when(event.getPlayer()).thenReturn(player);
+    var sessions = new ResonanceSessionManager();
+    when(Magic.plugin.getResonanceGuiManager().getSessionManager()).thenReturn(sessions);
+    var session = sessions.getOrCreate(player);
+    listener.onSkillCast(event);
+    assertEquals(0., session.getEquilibrium());
+    verify(Magic.plugin, never()).syncSpellModifiers(player, session);
+  }
+}