Adopt scripts-to-rule-them-all: script/ entrypoints, Makefile shims

script/lint

@@ -0,0 +1,14 @@
+#!/bin/sh
+# script/lint: run the linter.
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    # CGO is required (Makefile exports this too)
+    export CGO_ENABLED=1
+    golangci-lint run --timeout 5m
+}
+
+main "$@"