Support other agents' transcripts

I do feel a bit of regret naming the library so explicitly after Claude Code back in the days and sometimes wonder if we should support other agents' transcript formats. But maybe this is not a huge issue as Github supports redirects, though not sure about pypi.

I think the code is well structured and abstracted for implementing other parsers. I haven't used other agents enough though to know if they have very different concepts and use cases that might complicate the DAG and rendering. I did use Pi a bit to know that it's super customisable, but not sure how much the plugins would change the transcript? I guess they would need to to make the sessions resumable?

My biggest concern is that each of these agents are going quite fast and it's been challenging enough to keep up with Claude Code only. That said, most of the other ones are open source, so it might be possible to implement a semi-deterministic way to extract their transcript format and semantics.

No specific agent, transcript format, files, tests, or entry point is named. Start by identifying one target agent and documenting how its transcript concepts map to the existing parser, DAG, rendering, and resumability behavior; done would require an agreed format scope and corresponding implementation and tests.