fix(frontend): match the reference post format options in the page set modal

参考主题把文章格式固定为标准/图像/画廊/视频四项，动态读取
get_theme_support('post-formats') 会让本站多出 aside/quote/link
等注册格式，选项集偏离参考主题，故改为固定列表。

tests/widget-system/frontend-page-edit-harness.php

@@ -21,6 +21,7 @@ namespace {
 	$GLOBALS['aksrt_set_page_templates']  = [];
 	$GLOBALS['aksrt_set_can']             = true;
 	$GLOBALS['aksrt_set_scripts']         = [];
+	$GLOBALS['aksrt_set_post_format']     = '';
 
 	function __(string $text, string $domain = ''): string { return $text; }
 	function esc_html__($t, $d = ''): string { return (string) $t; }
@@ -48,7 +49,7 @@ namespace {
 	function update_post_meta($id, $key, $value): void { $GLOBALS['aksrt_set_meta'][$key] = $value; }
 	function get_the_title($id): string { return '示例标题'; }
 	function get_the_permalink($id): string { return 'https://example.test/post'; }
-	function get_post_format($id) { return ''; }
+	function get_post_format($id) { return $GLOBALS['aksrt_set_post_format'] ?? ''; }
 	function set_post_format($id, $format): void { $GLOBALS['aksrt_set_meta']['__format'] = $format; }
 	function post_type_supports($type, $feature): bool { return $feature === 'post-formats'; }
 	function get_theme_support($feature) { return $feature === 'post-formats' ? [['image', 'video']] : false; }
@@ -290,6 +291,29 @@ namespace {
 	}
 	set_check(strpos($modal_icons, 'class="fa fa-') === false, 'modal must not use bare FA4 icon classes');
 
+	// 文章格式：参考主题固定 standard/图像/画廊/视频 四项，不读主题注册集。
+	// 无格式时 WP 的 selected() 不选中任何项，浏览器默认落到第一项 standard。
+	$format_block = substr($modal_icons, (int) strpos($modal_icons, 'name="post_format"'));
+	$format_block = substr($format_block, 0, (int) strpos($format_block, '</select>'));
+	set_check($format_block !== '', 'post inputs must include the post_format select');
+	$option_order = [];
+	preg_match_all('/<option[^>]*value="([^"]*)"/', $format_block, $m);
+	$option_order = $m[1];
+	set_check($option_order === ['standard', 'image', 'gallery', 'video'], 'post format options must mirror the reference order');
+	set_check(strpos($format_block, '>图像<') !== false, 'post format must use the reference 图像 label');
+	set_check(strpos($format_block, '>画廊<') !== false, 'post format must use the reference 画廊 label');
+	set_check(strpos($format_block, '>视频<') !== false, 'post format must use the reference 视频 label');
+	foreach (['aside', 'quote', 'link'] as $extra) {
+		set_check(strpos($modal_icons, "value=\"{$extra}\"") === false, "post format options must not leak the theme-only format {$extra}");
+	}
+	// 已设置格式时必须回显选中项。
+	$GLOBALS['aksrt_set_meta']['__format'] = '';
+	$GLOBALS['aksrt_set_post_format'] = 'image';
+	ob_start();
+	(new PageAdminSet())->render_modal();
+	$modal_image = (string) ob_get_clean();
+	set_check(strpos($modal_image, '<option selected="selected" value="image">') !== false, 'the active format must render as selected');
+
 	$gear = (new PageAdminSet())->float_button('', false);
 	set_check(strpos($gear, 'fa fas fa-cog fa-spin') !== false, 'the gear must use the FA5 cog class');