feat(studio): reflect account-voice / series-scope field split

Robot-author edit form and detail drop positioning/target_readers (now
series-level); persona + styles stay (routed to the account profile via the
admin API). Series detail shows positioning/target_readers. Types updated;
admin API types regenerated.

src/routes/_authed/studio/series.tsx

@@ -63,6 +63,8 @@ function SeriesPage() {
           { label: 'ID', value: <code className="font-mono text-xs">{detail?.id}</code> },
           { label: '状态', value: detail && <StatusPill status={detail.status} /> },
           { label: '计划篇数', value: detail?.target_article_count },
+          { label: '内容定位', value: detail?.positioning },
+          { label: '目标读者', value: detail?.target_readers },
           { label: '读者旅程', value: detail?.reader_journey },
           {
             label: '作者',