Switch to 'bleedingedge' branch for now

[iwr-redmond]

The bleedingedge branch of stable-diffusion.cpp, which is maintained by @stduhpf, was recently suggested as a better base for downstream applications, given the ongoing absence of the original maintainer @leejet.

It may be helpful to switch stable-diffusion-cpp-python to this branch until a more permanent change can be implemented in partnership with the ggml-org.

Note that the downstream Nexa SDK is expected to have a major update soon, and this proposed change would facilitate the incorporation of the various fixes from bleedingedge into that larger package.

[stduhpf]

Just be aware that the bleedingedge branch is called "bleedingdge" for a reason. It's not supposed to be stable, it's just a branch where I merged in whichever experimental features I liked (this does include a few bug fixes though).

[iwr-redmond]

IIUC you've been cherry-picking specific PRs to add, and it's probably as stable as the unmaintained 'main' branch but under-tested due to the fragmentation that currently exists. Is that more or less correct?

[william-murray1204]

With @leejet's recent return, it makes sense to observe how the main project progresses. If development stalls, I’ll set aside some time to build a separate bleeding-edge install. In the meantime, I’ve updated the stable-diffusion-cpp-python package to the latest stable-diffusion.cpp release, with added support for Flux Kontext and Chroma.