feat(web): nav regroup, site RSS tab and site types (IA-2)

- sidebar: 概览 / 获取 / 整理 / 系统. Tasks moves to 系统; sites,
  subscriptions and rules form the 获取 group (ACQUIRE_GROUP_TITLE in
  nav.ts, the single place to rename it); standalone RSS nav item removed
- site detail gets an RSS tab with everything the RSS page had (create,
  edit, enable, fetch now, fetch state) plus recent items; tabs and
  header actions follow the site's capabilities
- old /console/sources links redirect to the site's RSS tab (?feed= looks
  up the owning site) or the site list; task links to RSS point at sites
- site list shows and filters by type; add-site wizard starts with a type
  step (PT still picks from the definition library; public BT / custom
  RSS source only need name, URL and RSS URL)

Co-Authored-By: Claude Opus 5.5 <[email protected]>

apps/web/app/components/downloads/business-tasks.tsx

@@ -81,7 +81,8 @@ export function subjectLink(t: Pick<Task, "subjectType" | "subjectId">): string
     case "site":
       return consolePath("sites", t.subjectId);
     case "feed_source":
-      return consolePath("sources");
+      // RSS 属于站点(IA-2):按 ?feed= 查所属站点后跳到站点的 RSS Tab
+      return `${consolePath("sources")}?feed=${encodeURIComponent(t.subjectId)}`;
     default:
       return null;
   }