feat(float): rebuild right floating buttons 1:1 with reference theme

- Storage: aksrt_floating_buttons now uses reference float_btn shape
  (fixed 8 sortable types, more-buttons group); single source of
  defaults/sanitize in AKSRT\Settings\FloatButtons
- Admin SPA: CSF-parity page split into components/floating/*
- Frontend: aksrt_float_right() on wp_footer mirrors zib_float_right()
  (wp_is_mobile, PC tooltip, toggle-theme, ontop/scrollTopTo, qrcode,
  wechat/qq, pay_vip, add, more)
- CSS: floating-buttons.css rewritten from reference rules; legacy float
  rules removed from main/part/shell/overlay-primitives
- Remove dead code: reorder route/API, get_floating_buttons_items,
  floatingSchema, floatActionsId, float-theme-toggle bindings,
  common/floating.css, aksrt-runtime-win.php, .aksrt-float-btn

src/Settings/CategoryIntegrationGroups.php

@@ -106,21 +106,12 @@ trait CategoryIntegrationGroups {
     }
 
     /**
-     * 获取右侧浮动按钮完整配置
-     * @return array {enabled, style, position, scroll_hide, scroll_down_hide, filter_blur, items}
+     * 获取右侧浮动按钮完整配置（结构见 FloatButtons::defaults()）。
      */
     public static function get_floating_buttons_settings(): array {
         return Integration::get_floating_buttons_settings();
     }
 
-    /**
-     * 获取右侧浮动按钮项（仅返回启用的，按排序）
-     * @return array
-     */
-    public static function get_floating_buttons_items(): array {
-        return Integration::get_floating_buttons_items();
-    }
-
     /**
      * Customizer 注册（可选）
      */