feat(tenant/kol): let KOLs self-subscribe to their own published packages

Add /kol/manage/packages/:id/self-subscription POST/DELETE on the tenant
side so a KOL can grant themselves access to their own published package
without going through the marketplace approval flow. Reject self-subscribe
through the marketplace with a clear error, expose owned_by_current_tenant
on package responses, and surface a self_subscription block on KolPackage
Response. The admin-web KOL workspace gets 订阅自己 / 取消订阅 entries with
matching messaging in the marketplace detail view.

Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>

packages/shared-types/src/index.ts

@@ -1578,6 +1578,8 @@ export interface KolPackageSummary {
   status: "draft" | "published" | "archived";
   prompt_count: number;
   subscriber_count: number;
+  owned_by_current_tenant?: boolean;
+  self_subscription?: KolSubscription | null;
   created_at: string;
   updated_at: string;
 }