allow integration with other git web frontends

This tool would provide the most value when integrated with other web frontends to git. Since the webserving section of the code is so lightweight, this should not be hard to do.

One route might be to keep the existing webserver running on a different port to the other frontend and then embed the graph visualization via ``. However that probably wouldn't allow the tight integration which would deliver most value, e.g. being able to click on a commit in the graph to visit that commit in the frontend. It would also suffer from the restriction of one graph server (and hence TCP port) per repository.

I'd love to hear ideas from web frontend maintainers on this.

Start by reviewing the webserving section and the existing graph visualization entry points. Consult maintainers of other git web frontends to establish an integration approach. Done should include tight frontend integration, clickable commits that open the corresponding frontend page, and a solution to the one-graph-server-per-repository limitation.

Written by the indexing model from the issue text.