feat(widgets): rebuild admin widgets page to match reference theme

- Replace transfer modal/admin-post flow with reference-style AJAX
  export/import/template dialogs (admin-transfer.js, TransferController)
- Customizer "移出模块" action, reference lazy form loading with t-notice
- Common fields use reference labels, dependencies, compact/inline rows,
  top/bottom-only extra spacing; form header with description/reminder
- Remove placement hint, template preview and legacy transfer code
- Fix widget audit (current_datetime stub, honor catalog common flags)
  and regenerate stale golden fixtures for posts_toc, quote, posts

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/WidgetSystem/SchemaWidget.php

@@ -41,11 +41,11 @@ final class SchemaWidget extends \WP_Widget {
 			$this->render_lazy_placeholder();
 			return;
 		}
-		FormRenderer::render($this, $this->definition->fields(), $instance);
+		FormRenderer::render($this, $this->definition->form_fields(), $instance);
 	}
 
 	public function render_full_form(array $instance): void {
-		FormRenderer::render($this, $this->definition->fields(), array_merge($this->definition->defaults(), $instance));
+		FormRenderer::render($this, $this->definition->form_fields(), array_merge($this->definition->defaults(), $instance));
 	}
 
 	public function update($new_instance, $old_instance): array {
@@ -65,11 +65,10 @@ final class SchemaWidget extends \WP_Widget {
 
 	private function render_lazy_placeholder(): void {
 		printf(
-			'<div class="aksrt-widget-form-lazy" data-id-base="%1$s" data-widget-number="%2$s"><p class="aksrt-widget-form-lazy__status">%3$s</p><button type="button" class="button aksrt-widget-form-lazy__load">%4$s</button></div>',
+			'<div class="aksrt-widget-form-lazy" data-id-base="%1$s" data-widget-number="%2$s"><div class="aksrt-widget-form-lazy__status"><div class="t-notice t-loading">%3$s</div></div></div>',
 			esc_attr($this->id_base),
 			esc_attr((string) $this->number),
-			esc_html__('配置将在展开或添加模块后加载。', 'aksrt'),
-			esc_html__('加载配置', 'aksrt')
+			esc_html__('正在加载模块配置…', 'aksrt')
 		);
 	}
 }