fix(Core/Unit): restore immediate combat engagement for non-controllable guardians (#26654)

src/server/game/Entities/Unit/Unit.cpp

@@ -7425,15 +7425,17 @@ bool Unit::Attack(Unit* victim, bool meleeAttack)
     else if (victim->IsCreature())
         victim->ToCreature()->UpdateLeashExtensionTime();
 
-    // set position before any AI calls/assistance
-    //if (IsCreature())
-    //    ToCreature()->SetCombatStartPosition(GetPositionX(), GetPositionY(), GetPositionZ());
-    // player-controlled creatures (pets, charms) enter combat on contact instead
-    // (melee swing execution or spell launch/hit, see Unit::AtTargetAttacked)
-    if (creature && !IsControlledByPlayer())
+    // Player-controlled creatures (pets, charms) enter combat on contact instead
+    // (melee swing execution or spell launch/hit, see Unit::AtTargetAttacked).
+    // Non-controllable guardians (e.g. Shaman Elementals, Infernal) have no attack
+    // command and must engage immediately so their AI can chase and attack.
+
+    if (creature && (!IsControlledByPlayer() || (IsGuardian() && !IsControllableGuardian())))
     {
         EngageWithTarget(victim);
 
+        if (!IsControlledByPlayer())
+        {
             creature->SendAIReaction(AI_REACTION_HOSTILE);
 
             /// @todo: Implement aggro range, detection range and assistance range templates
@@ -7444,6 +7446,7 @@ bool Unit::Attack(Unit* victim, bool meleeAttack)
 
             SetUInt32Value(UNIT_NPC_EMOTESTATE, EMOTE_ONESHOT_NONE);
         }
+    }
 
     // delay offhand weapon attack by 50% of the base attack time
     if (HasOffhandWeaponForAttack() && isAttackReady(OFF_ATTACK))