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

script/test

@@ -0,0 +1,18 @@
+#!/bin/sh
+# script/test: run the test suite. Quiet on success; on failure, rerun
+# verbosely for full diagnostic output (the exit 1 ensures the rerun
+# never turns a failure into a pass).
+set -eu
+
+ROOT="$(cd "$(dirname "$0")/.." && pwd -P)"
+
+main() {
+    cd "$ROOT"
+    go test -race -timeout 30s ./... || {
+        echo "--- Rerunning with -v for details ---"
+        go test -race -timeout 30s -v ./...
+        exit 1
+    }
+}
+
+main "$@"