B7 review-response batch: derived about counter, CJK-aware reading time, ZH copy fixes, hero leads with capability

src/lib/reading-time.ts

@@ -0,0 +1,35 @@
+/**
+ * Reading time and word count that also work for Chinese.
+ *
+ * A whitespace split is meaningless for CJK prose: an entire Chinese article has
+ * almost no interior spaces, so it counted as one "word" and every ZH post showed
+ * "1 min read" while its English twin showed five. CJK ideographs are counted as
+ * characters (~400/min); everything else keeps the existing ~200 words/min.
+ *
+ * For pure-ASCII bodies the result is identical to the old whitespace/200 maths.
+ */
+
+const CJK_CHAR = /[\u3040-\u30ff\u3400-\u4dbf\u4e00-\u9fff\uf900-\ufaff\uac00-\ud7af]/;
+
+function counts(body?: string): { cjk: number; latin: number } {
+  const text = body ?? '';
+  const cjk = (text.match(new RegExp(CJK_CHAR.source, 'g')) ?? []).length;
+  const latin = text
+    .replace(new RegExp(CJK_CHAR.source, 'g'), ' ')
+    .trim()
+    .split(/\s+/)
+    .filter(Boolean).length;
+  return { cjk, latin };
+}
+
+/** Total count used for schema.org `wordCount` (CJK counts per character). */
+export function countWords(body?: string): number {
+  const { cjk, latin } = counts(body);
+  return cjk + latin;
+}
+
+/** Minutes of reading time, never below 1. */
+export function readingMinutes(body?: string): number {
+  const { cjk, latin } = counts(body);
+  return Math.max(1, Math.round(cjk / 400 + latin / 200));
+}