fix(Core/Unit): start pet combat on contact instead of on attack command (#26463)

Co-authored-by: Claude Fable 5 <noreply@anthropic.com>
Co-authored-by: sogladev <sogladev@gmail.com>

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

@@ -7425,12 +7425,12 @@ bool Unit::Attack(Unit* victim, bool meleeAttack)
     // set position before any AI calls/assistance
     //if (IsCreature())
     //    ToCreature()->SetCombatStartPosition(GetPositionX(), GetPositionY(), GetPositionZ());
-    if (creature)
+    // player-controlled creatures (pets, charms) enter combat on contact instead
+    // (melee swing execution or spell launch/hit, see Unit::AtTargetAttacked)
+    if (creature && !IsControlledByPlayer())
     {
         EngageWithTarget(victim);
 
-        if (!IsControlledByPlayer())
-        {
         creature->SendAIReaction(AI_REACTION_HOSTILE);
 
         /// @todo: Implement aggro range, detection range and assistance range templates
@@ -7441,7 +7441,6 @@ 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))