chore: .gitignore, 씬 및 UI/무기 디렉토리 업데이트

- .gitignore: External packages, Sketchfab, Wwise 무시 추가
- Colosseum.slnx: 솔루션 파일 업데이트
- Test.unity: 게임 매니저 및 UI 연동
- UI/, Weapons/ 디렉토리 추가

Ultraworked with [Sisyphus](https://github.com/code-yeongyu/oh-my-opencode)

Co-authored-by: Sisyphus <clio-agent@sisyphuslabs.ai>

Assets/Weapons/NewWeapon.asset

@@ -0,0 +1,31 @@
+%YAML 1.1
+%TAG !u! tag:unity3d.com,2011:
+--- !u!114 &11400000
+MonoBehaviour:
+  m_ObjectHideFlags: 0
+  m_CorrespondingSourceObject: {fileID: 0}
+  m_PrefabInstance: {fileID: 0}
+  m_PrefabAsset: {fileID: 0}
+  m_GameObject: {fileID: 0}
+  m_Enabled: 1
+  m_EditorHideFlags: 0
+  m_Script: {fileID: 11500000, guid: 52134ecd4c816f64888d34b2163e7af1, type: 3}
+  m_Name: NewWeapon
+  m_EditorClassIdentifier: Colosseum.Game::Colosseum.Weapons.WeaponData
+  weaponName: "\uAC80"
+  description: 
+  icon: {fileID: 21300000, guid: 70e07ab1b9f326b4bae30fe839d609ea, type: 3}
+  weaponSlot: 0
+  weaponPrefab: {fileID: 1631607032641582, guid: 92cfe4029ea2b754caa0b3f00d52d41a, type: 3}
+  positionOffset: {x: 0, y: 0, z: 0}
+  rotationOffset: {x: 0, y: 0, z: 0}
+  scale: {x: 1, y: 1, z: 1}
+  strengthBonus: 0
+  dexterityBonus: 0
+  intelligenceBonus: 0
+  vitalityBonus: 0
+  wisdomBonus: 0
+  spiritBonus: 0
+  damageMultiplier: 1
+  rangeMultiplier: 1
+  manaCostMultiplier: 1