refactor: share sampled entry summary formatting

src/shared/string-sample.ts

@@ -0,0 +1,14 @@
+export function summarizeStringEntries(params: {
+  entries?: ReadonlyArray<string> | null;
+  limit?: number;
+  emptyText?: string;
+}): string {
+  const entries = params.entries ?? [];
+  if (entries.length === 0) {
+    return params.emptyText ?? "";
+  }
+  const limit = Math.max(1, Math.floor(params.limit ?? 6));
+  const sample = entries.slice(0, limit);
+  const suffix = entries.length > sample.length ? ` (+${entries.length - sample.length})` : "";
+  return `${sample.join(", ")}${suffix}`;
+}