feat: 添加应用图标搜索功能及相关页面

新增应用图标搜索功能，包括搜索表单、图标展示、加载更多和返回顶部按钮。页面结构、样式和交互逻辑均已实现。

old/js/scripts.js

@@ -0,0 +1,43 @@
+document.addEventListener("DOMContentLoaded", function() {
+    const loadMoreButton = document.getElementById("load-more");
+    const backToTopButton = document.getElementById("back-to-top");
+
+    if (loadMoreButton) {
+        loadMoreButton.addEventListener("click", function() {
+            let offset = parseInt(this.getAttribute("data-offset"));
+            const searchTerm = this.getAttribute("data-term");
+            const limit = 40;
+
+            fetch(`index.php?term=${searchTerm}&offset=${offset}`)
+    .then(response => response.text())
+    .then(data => {
+        const tempDiv = document.createElement('div');
+        tempDiv.innerHTML = data;
+        const newContent = tempDiv.querySelectorAll('.icon-grid div');
+        newContent.forEach(item => document.querySelector('.icon-grid').appendChild(item));
+        // 更新偏移量
+        loadMoreButton.setAttribute("data-offset", offset + limit);
+    });
+
+        });
+    }
+
+    // 显示返回顶部按钮的逻辑
+    window.onscroll = function() {
+        if (document.body.scrollTop > 100 || document.documentElement.scrollTop > 100) {
+            backToTopButton.style.display = "block";
+        } else {
+            backToTopButton.style.display = "none";
+        }
+    };
+
+    // 返回顶部按钮点击事件
+    backToTopButton.onclick = function() {
+        window.scrollTo({ top: 0, behavior: 'smooth' });
+    };
+});
+document.getElementById('submit').addEventListener('keydown', function(event) {
+    if (event.key === 'Enter') {
+        searchMovies(); // 按下回车键时执行搜索
+    }
+});