install source selection

i live in a place where comfy registry don't allow package instalation, and install by hand using git url does not always work.

an example: today i had to install [enricos node](https://github.com/erosDiffusion/ComfyUI-enricos-nodes) but comfy registry didn't let me, so i copied the url and tried installing from git url, but then tells me he doesn't find a node, but if a use a vpn and try to install the normal way and choose nightly then the node install's well

so can you implement a source installation option? or i might be missing something?

Start in ComfyUI-Manager by tracing the existing registry and git URL installation paths, then reproduce the reported behavior with the enricos-nodes repository. Compare that result with installing the node through the registry using the nightly source; done means a clear source-selection option can install the same node without requiring a VPN.

Written by the indexing model from the issue text.