7.22.3

Bump Go to 1.27.3

Updates the go directive in go.mod from 1.26.8 to 1.27.3, moving the
project onto the current Go 1.27 release line.

go mod tidy made no dependency changes -- go.sum is unchanged. Its only
other edit was merging the two adjacent require blocks into one.

Co-Authored-By: Claude Opus 5 <noreply@anthropic.com>