feat(runtime): 全站前端脚本统一接入 AksrtFrontend 全局 DOM 生命周期

- rehydrate.js 新增 boot()/aksrt:ready 事件，支持 boot 后晚注册立即以 init 触发
- aksrt-runtime.js 初始加载改走 AksrtFrontend.boot，tooltip/倒计时注册为组件
- 约 30 个前端脚本（首页、评论、支付、路由、页面叶子、widgets）
  从直接 DOMContentLoaded 迁移为 AksrtFrontend.register，并加幂等标记
- section-navs 依赖改为 aksrt-runtime，保证注册时序
- 清理死代码：删除孤儿 loader.js/main.js 及 runtime/page-navs 遗留副本
- loader.js 移除已迁移模块的 tbquire 路径映射，main.js 相应瘦身
- build-public-assets.mjs 增加 runtime/main.min.js 自动压缩步骤
- 新增 4 个契约测试（homepage-dom/rehydrate-runtime/global-dom-init/
  public-bundle-parity），3 个既有 harness 适配注册表初始化方式

assets/js/input-expand.js

@@ -37,9 +37,17 @@
 
   // ── Auto-resize Textarea ──
 
-  function initAutoResize() {
-    var textareas = document.querySelectorAll('textarea[data-aksrt-autoresize]');
+  function queryAll(root, selector) {
+    var nodes = Array.prototype.slice.call(root.querySelectorAll(selector));
+    if (root.nodeType === 1 && root.matches(selector)) nodes.unshift(root);
+    return nodes;
+  }
+
+  function initAutoResize(root) {
+    var textareas = queryAll(root, 'textarea[data-aksrt-autoresize]');
     textareas.forEach(function (ta) {
+      if (ta.dataset.aksrtAutoresizeBound === '1') return;
+      ta.dataset.aksrtAutoresizeBound = '1';
       function resize() {
         ta.style.height = 'auto';
         ta.style.height = ta.scrollHeight + 'px';
@@ -52,9 +60,11 @@
 
   // ── Character Counter ──
 
-  function initCounters() {
-    var fields = document.querySelectorAll('[data-aksrt-counter]');
+  function initCounters(root) {
+    var fields = queryAll(root, '[data-aksrt-counter]');
     fields.forEach(function (field) {
+      if (field.dataset.aksrtCounterBound === '1') return;
+      field.dataset.aksrtCounterBound = '1';
       var max = parseInt(field.getAttribute('data-aksrt-maxlength') || field.getAttribute('maxlength') || '0', 10);
       var counter = document.createElement('span');
       counter.className = 'aksrt-counter';
@@ -79,9 +89,11 @@
 
   // ── Validation Feedback ──
 
-  function initValidation() {
-    var fields = document.querySelectorAll('[data-aksrt-validate]');
+  function initValidation(root) {
+    var fields = queryAll(root, '[data-aksrt-validate]');
     fields.forEach(function (field) {
+      if (field.dataset.aksrtValidateBound === '1') return;
+      field.dataset.aksrtValidateBound = '1';
       var minLen = parseInt(field.getAttribute('data-aksrt-minlength') || field.getAttribute('minlength') || '0', 10);
       var maxLen = parseInt(field.getAttribute('data-aksrt-maxlength') || field.getAttribute('maxlength') || '0', 10);
       var required = field.hasAttribute('required');
@@ -115,16 +127,13 @@
 
   // ── Main Init ──
 
-  function init() {
+  function init(root) {
+    root = root || document;
     injectStyle();
-    initAutoResize();
-    initCounters();
-    initValidation();
+    initAutoResize(root);
+    initCounters(root);
+    initValidation(root);
   }
 
-  if (document.readyState === 'loading') {
-    document.addEventListener('DOMContentLoaded', init);
-  } else {
-    init();
-  }
+  window.AksrtFrontend.register('aksrt-input-expand', init);
 })();