fix(admin): replicate reference front-submit settings page 1:1

- Rewrite post_list/submit schema (PHP + JS) with the reference theme's
  field set, order, defaults and dependencies; topics fields excluded
- Map PostDisplay::get_submit_settings() and the FrontSubmit runtime to
  the new keys without legacy fallback
- Guest submission follows the capability matrix; category required on
  submit; pay limits read from the cash/points fieldset
- Drop dead front_submit_* settings, template branches and JS config
- Add submit settings reference contract test

src/Core/FrontSubmitSave.php

@@ -32,7 +32,7 @@ trait FrontSubmitSave {
         }
 
         if ($is_guest) {
-            if (empty($settings['guest_enabled']) || (int) $settings['default_user_id'] <= 0) {
+            if ((int) $settings['default_user_id'] <= 0) {
                 return ['success' => false, 'message' => __('请先登录', 'aksrt')];
             }
             if ($is_draft) {
@@ -93,19 +93,16 @@ trait FrontSubmitSave {
             if ($this->text_length(wp_strip_all_tags($content)) < 10) {
                 return ['success' => false, 'message' => __('文章内容过少', 'aksrt')];
             }
-            if (!empty($settings['allow_category']) && empty($categories)) {
+            if (empty($categories)) {
                 return ['success' => false, 'message' => __('请选择文章分类', 'aksrt')];
             }
-            if (!empty($settings['cover_required']) && empty($data['featured_data']) && empty($data['thumbnail'])) {
-                return ['success' => false, 'message' => __('请设置封面图', 'aksrt')];
-            }
         }
 
         // Allowed category whitelist.
         $allowed = $settings['allowed_cat_ids'] ?? [];
         if (!empty($allowed) && !empty($categories)) {
             $categories = array_values(array_intersect($categories, $allowed));
-            if (!$is_draft && empty($categories) && !empty($settings['allow_category'])) {
+            if (!$is_draft && empty($categories)) {
                 return ['success' => false, 'message' => __('所选分类不可用', 'aksrt')];
             }
         }
@@ -126,7 +123,7 @@ trait FrontSubmitSave {
 
         $status = 'draft';
         if (!$is_draft) {
-            $status = $this->resolve_publish_status($user_id, $settings);
+            $status = $this->resolve_publish_status($user_id);
         }
 
         $can_iframe = $this->user_can_cap('new_post_iframe_video', $user_id);
@@ -173,7 +170,7 @@ trait FrontSubmitSave {
         }
 
         // Re-apply categories when empty update should clear (logged-in only).
-        if (!empty($settings['allow_category']) && isset($data['category'])) {
+        if (isset($data['category'])) {
             wp_set_post_categories((int) $in_id, $categories);
         }
         if (!empty($settings['allow_tags']) && array_key_exists('tags', $data) && $tags_raw === '') {
@@ -233,17 +230,12 @@ trait FrontSubmitSave {
     }
 
     /**
-     * @param array<string, mixed> $settings
+     * Publish status for a non-draft submission.
+     *
+     * Mirrors the reference theme: pending unless the user holds the
+     * "publish without review" capability.
      */
-    private function resolve_publish_status(int $user_id, array $settings): string {
-        $mode = (string) ($settings['review_mode'] ?? 'pending');
-        if ($mode === 'draft') {
-            return 'draft';
-        }
-        if ($mode === 'publish') {
-            return 'publish';
-        }
-        // pending mode: skip audit when capability grants it.
+    private function resolve_publish_status(int $user_id): string {
         if ($this->user_can_cap('new_post_audit_no', $user_id)) {
             return 'publish';
         }