The MIN_LOC=100 threshold checked total diff lines, not instrumentable
lines. A commit with many non-instrumentable lines (structs, comments)
but only 1-2 instrumentable lines would unfairly fail at 0% coverage.
Add a minimum instrumentable lines threshold (5) so the check skips
when the sample size is too small to be meaningful.
Extract duplicated respondWithError closures into a single package-level
function. Guard against nil ImageId in handleEC2RunInstances to prevent
panic under race conditions. Fix diff-coverage base ref for main branch.
Julian Sommer