Format Go with gofmt, then golines -m 77 (closes #215)

script/fmt now runs golines -m 77 after gofmt, repeating golines until
it changes nothing, since one pass can leave a line the next splits.
script/fmt-check fails when either would change a file.
script/bootstrap installs golines v0.13.0 with go install, pinned to
its commit, and checks the installed version with go version -m.

The tree is reformatted. The longer lines this makes are fixed by
hand: nolint directives moved onto their own line above the statement,
one string split, and 20 functions over funlen's 80 lines shortened or
split, RunWAF and limitPercentages among them.

Model: opus-5-5

script/fmt-check

@@ -1,6 +1,6 @@
 #!/bin/sh
 # script/fmt-check: check formatting (read-only): the Go code with
-# gofmt, the Markdown with prettier.
+# gofmt and golines -m 77, the Markdown with prettier.
 set -eu
 
 ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
@@ -24,14 +24,33 @@ run_yarn() {
         shift && exec yarn "$@"' bash "$NODE_VERSION" "$@"
 }
 
+# The golines that script/bootstrap installed: go install puts it in
+# GOBIN, or in GOPATH/bin when GOBIN is unset.
+golines_path() {
+    gobin="$(go env GOBIN)"
+    golines="${gobin:-$(go env GOPATH)/bin}/golines"
+    if [ ! -x "$golines" ]; then
+        echo "fmt-check: no golines; run script/bootstrap first" >&2
+        exit 1
+    fi
+    echo "$golines"
+}
+
 main() {
     cd "$ROOT"
+    golines="$(golines_path)"
     unformatted="$(gofmt -l cmd internal)"
     if [ -n "$unformatted" ]; then
         echo "fmt-check: gofmt would change:" >&2
         echo "$unformatted" >&2
         exit 1
     fi
+    unformatted="$("$golines" -m 77 -l cmd internal)"
+    if [ -n "$unformatted" ]; then
+        echo "fmt-check: golines -m 77 would change:" >&2
+        echo "$unformatted" >&2
+        exit 1
+    fi
     run_yarn run prettier --check '**/*.md' --tab-width 4 --prose-wrap always
 }