symphony-learn

Update a vendored git submodule (torchtitan, torchft, or any future fork-based submodule) to a newer upstream version while preserving Panocular's custom changes that live on top of upstream. Use this whenever the user wants to "update torchtitan/torchft", "update the submodules", "pull in upstream changes", "rebase our fork", "bump a submodule", "sync the fork with upstream", or resolve conflicts between our changes and new upstream code. Trigger even if the user only names one submodule or just says "update the submodule".