feat(nav): deep 1:1 zibll search-box + navbar-search + newposts unify

Port aksrt_get_search_box/posts for menu_search and layout 1/3 slide;
unify publish switch; expand user-box admin row; CSS/JS remote-box parity.

tools/nav-zibll-contract-report.txt

@@ -1 +1,6 @@
-PASS full-push deep nav contracts
+PASS deep nav contracts (search-box DOM + remote menu_search + navbar-search slide + unified newposts)
+- aksrt_get_search_box / aksrt_get_search_posts present
+- menu_search AJAX wraps .dropdown-menu.hover-show-con > .search-input
+- layout1/3 templates/parts/navbar-search.php
+- header_newposts_enabled single switch; publish_btn mirrors
+- user box admin row: 主题设置/模块布局/商城中心/后台