Any instruction on how to debug the client app?

- [x] I have checked that a similar [feature request](https://github.com/Genymobile/scrcpy/issues?q=is%3Aopen+is%3Aissue+label%3A%22feature+request%22) does not already exist.

**Is your feature request related to a problem? Please describe.**
I tried to do some development on top of scrcpy client. However I can't get the debug to start. I am using vscode with msys64.

**Describe the solution you'd like**
A instruction on how your debug environment looks like. Does not have to be using vscode.

**Describe alternatives you've considered**
Tried to visual studio, but it is too heavy to install it.

**Additional context**
N/A

The issue names the scrcpy client and a VSCode with MSYS64 setup, but no file, test, or entry point. Start by locating the client build and debug entry points, then document a reproducible debug setup and verify that the instructions let a developer start the client under a debugger.

Written by the indexing model from the issue text.