[Feature] Could u Add an external shared folder Or ContentProvider to add charts?

### Is your feature request related to a problem?

Adding storefronts requires proficiency in file management, which leads to a decrease in user interaction experience

### Describe the feature

Add an external shared folder Or ContentProvider to add charts
Please,I want to change the chart in another ways

### Reason for adding

I want to develop a functionto add songs easily,beacuse of the reason which u need the root or suchs permission to change the file.
Also I want to base on it to develop another functions such as Community to share chart♥
Could u team have the project to support this function?

### Example(s)

_No response_

### Additional context

_No response_

The issue requests an external shared folder or ContentProvider to add charts, likely for a game or app. First, examine the codebase for existing chart management, file I/O, and Android ContentProvider usage. Determine how songs/charts are currently stored and loaded. The goal is to design a system that allows external chart addition without root permissions, but the scope and specific implementation are undefined.

索引モデルが issue の本文から書いたものです。