feat(front-submit): 1:1 写文章/投稿页对齐 zibll newposts

Register AKSRT 写文章/投稿 page template, wire header publish entry to
front submit URL, rewrite page-submit as dual-column TinyMCE compose with
featured cover, multi-category/topics/filters, pay box, drafts, and
capability-gated FrontSubmit AJAX (pay/featured traits).

assets/css/frontend/pages.css

@@ -3,3 +3,4 @@
 @import url("pages/topic-rows.css");
 @import url("pages/sidebar.css");
 @import url("pages/empty-state.css");
+@import url("pages/submit.css");