2023.0501.0

• [bug] Fix cannot entry to the gameplay. #1941
• [skin][Stage] Create the cover skin element. #1908
• [enhancement] Implement CurrentStageInfo in the karaoke beatmap. #1905
• [enhancement][mod] Create stage mod. #1878
• [enhancement] Implement the classic stage info auto-generator. #1764
• [enhancement] Implement stage class as metadata in the karaoke beatmap #1755
• [code quality] Updating project to use File Scoped Namespaces #1754
• [bug] Help Andy to find his Airpods 2 #1513
• [bug] Fix cannot go to the gameplay. #1506
• [closed] Remove LayoutGroup class #902
• [enhancement][Design] Make preview section into pop-over in Layout editor #896