feat(enterprise-site): add WordPress support and scheduled auto-publish to sites

Add WordPress as an enterprise-site CMS type alongside pbootcms, and let
schedule tasks auto-publish generated articles to enterprise sites.

- WordPress connection/publisher service and tests; register wordpress
  media platform and relax cms_type CHECK constraint
- New publish_enterprise_site_targets JSONB column on schedule_tasks with
  array type constraint; thread targets through scheduler dispatch,
  prompt/KOL generation, and worker
- Admin UI: enterprise-site targets in generate/schedule/publish flows,
  KOL package form, MediaView, and i18n strings

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/migrations/20260609113000_add_schedule_enterprise_site_targets.up.sql

@@ -0,0 +1,6 @@
+ALTER TABLE schedule_tasks
+    ADD COLUMN publish_enterprise_site_targets JSONB NOT NULL DEFAULT '[]'::jsonb;
+
+ALTER TABLE schedule_tasks
+    ADD CONSTRAINT chk_schedule_tasks_publish_enterprise_site_targets_json
+        CHECK (jsonb_typeof(publish_enterprise_site_targets) = 'array');