qlog: align ErrorSpace with qlog spec

[KasenX]

This updates qlog ErrorSpace enum variants and call sites to match the spec (all versions) which uses "transport" and "application" instead of "transport_error" and "application_error".

[LPardue]

Thanks for the PR. This looks like a good change but I'd like to schedule it to come after https://github.com/cloudflare/quiche/pull/2168/changes which should happen soon

[KasenX]

Nice! I am looking forward to PR #2168. I’m currently implementing qlog for Nginx and found myself in the awkward position of having to use an outdated draft version because the qvis tool doesn't support the newer ones. However, I just discovered the qlog-dancer tool recently and using it instead of qvis will potentially allow me to implement the latest draft versions.

[juice928]

👋 Hi, I'm an automated AI code review bot. I ran some checks on this PR and found 1 point that might be worth attention (could be false positives, please use your judgment):

1. Ensuring backward compatibility for the ErrorSpace enum rename
   • Location: qlog/src/events/quic.rs:L209-L210
   • Impact: The rename changes serialized JSON values, which may prevent the application from reading older qlog files correctly during deserialization.
   • Suggestion: Consider adding #[serde(alias = "transport_error")] and #[serde(alias = "application_error")] to the new variants to maintain support for existing log formats.

If you find these suggestions disruptive, you can reply "stop" , and I'll automatically skip this repository in the future.

[LPardue]

For avoidance if doubt, we're going to purposefully break backwards compat in the next major qlog update PR, and this PR can do similar.