Description

c-c-c-combo! test by @tsmethurst, fix in https://codeberg.org/gruf/go-structr (our cache library) by myself

closes #3343

Checklist

[x] I/we have read the GoToSocial contribution guidelines.
[x] I/we have discussed the proposed changes already, either in an issue on the repository, or in the Matrix chat.
[x] I/we have not leveraged AI to create the proposed changes.
[x] I/we have performed a self-review of added code.
[x] I/we have written code that is legible and maintainable by others.
[x] I/we have commented the added code, particularly in hard-to-understand areas.
[ ] I/we have made any necessary changes to documentation.
[x] I/we have added tests that cover new code.
[x] I/we have run tests and they pass locally with the changes.
[x] I/we have run go fmt ./... and golangci-lint run.