Fix skill damage never actually scaling with level as its own comment claims

CCharacter::UseAtkSkill's hitmod formula was missing the "+ Stats->Level"
term that CCharacter::NormalAttack's equivalent hitmod already has --
despite the comment directly above it ("skill attacks now based on a
percentage of base attack power so that they scale with level")
promising exactly that. Net effect: a skill with atkpower=100 computed
the same base Attack as a plain auto-attack, but without the level
bonus or crit chance auto-attacks get, so skills ended up hitting no
harder (often weaker) than basic attacks.

This only touches genuine damage skills (skilltype 3/6 dispatched via
SKILL_ATTACK in worldpackets.cpp:pakStartSkill); buffs/heals/status
effects/resurrect (skilltype 9/11/13/20, SKILL_BUFF and friends) run
through entirely separate code and are untouched.

Co-Authored-By: Claude Sonnet 5 <noreply@anthropic.com>

Src/World Server/battle.cpp

@@ -737,7 +737,12 @@ void CCharacter::UseAtkSkill( CCharacter* Enemy, CSkills* skill, bool deBuff)
         {
             //unsigned int totalpower = skill->atkpower + Enemy->Stats->Magic_Defense;
             unsigned int totalpower = Attack + Enemy->Stats->Magic_Defense;
-            double hitmod = Attack * 100 / totalpower; //percentage of hitpower to use * 100
+            // + Stats->Level to match NormalAttack's hitmod (see battle.cpp
+            // NormalAttack) -- without it, skills never actually scaled with
+            // level despite the comment above claiming they do, and ended up
+            // hitting no harder than (often weaker than, since skills get no
+            // crit) a plain auto-attack.
+            double hitmod = Attack * 100 / totalpower + Stats->Level; //percentage of hitpower to use * 100
             hitpower = (unsigned int)floor((double)(hitmod * Attack / 100));
             //Log(MSG_DEBUG,"Skill magic: AP %i DEF %i",Stats->Attack_Power,Enemy->Stats->Defense);
             //Log(MSG_DEBUG,"Skill magic: Skill power %i. Attack %i",skill->atkpower,Attack);
@@ -747,7 +752,7 @@ void CCharacter::UseAtkSkill( CCharacter* Enemy, CSkills* skill, bool deBuff)
         {
             //unsigned int totalpower = skill->atkpower + Enemy->Stats->Defense;
             unsigned int totalpower = Attack + Enemy->Stats->Defense;
-            double hitmod = Attack * 100 / totalpower; //percentage of hitpower to use * 100
+            double hitmod = Attack * 100 / totalpower + Stats->Level; //percentage of hitpower to use * 100
             hitpower = (unsigned int)floor((double)(hitmod * Attack / 100));
             //Log(MSG_DEBUG,"Skill physical: AP %i DEF %i",Stats->Attack_Power,Enemy->Stats->Defense);
             //Log(MSG_DEBUG,"Skill physical: Skill power %i. Attack %i",skill->atkpower,Attack);