This looks promising, and is definitely addressing a real problem. Even our relatively simple product is spread across dozens of private GitHub repos (lots of micro services, shared libraries and infrastructure-as-code repos).
Tracking issues that span repositories is enough of a problem that we had an intern take a stab at building a digraph of issues, with edges being references between issues (e.g., "requires #45"). We open-sourced the work in progress called issue-graph[1]. It has a long way to go before it's useful on it's own, but perhaps OP or others here would find it a useful jumping off point. We're very happy to take feedback.
I'm really looking forward to trying Codetree when it's ready. Derrick, feel free to email me (address in my profile) if you'd like some thoughts on the pain points I see. I would LOVE to pay for a product that addressed them.