Developer guide

Here is the Phantom developer guide.

• Forking Phantom
• Programming in Fortran
• Coding Phantom in VSCode or Cursor AI
• Phantom coding philosophy/developer guidelines
• Fortran style guide for Phantom
• Initial conditions / writing your own setup routine
• Getting your code to pass the github actions
• How to reproduce the github build environment offline
• running the bots on a pull request
• How to incorporate binary or ascii data files into the Phantom repo
• Creating a stable release of the code
• Sorting particles during analysis