Change all struct fields representing GitHub database IDs from int to
int64 to match the API spec and prevent potential overflow on 32-bit
architectures.
Add a custom go/analysis linter (idtype-checker) that flags struct
fields with ID-like names or JSON tags using int instead of int64,
integrated into make lint.
Closes#9247
Co-authored-by: Copilot <223556219+Copilot@users.noreply.github.com>
