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

templates/parts/submit/context.php

@@ -175,8 +175,6 @@ if ($is_guest) {
 	$submit_label = __('审核', 'aksrt');
 } elseif ($edit_post && in_array($post_status, ['publish', 'pending'], true)) {
 	$submit_label = __('保存', 'aksrt');
-} elseif (($settings['review_mode'] ?? 'pending') === 'pending' && !$cap('new_post_audit_no')) {
-	$submit_label = __('审核', 'aksrt');
 }
 
 $ai_available = class_exists('\AKSRT\Ai\AI') && \AKSRT\Ai\AI::get_instance()->is_available();