feat: 新增App图标搜索器增强版功能

引入完整的App图标搜索器增强版，包括前端页面、后端缓存系统、样式和脚本。主要功能包括实时搜索、多尺寸图标下载、图片预览、响应式设计和智能缓存机制。后端通过ImageCache类实现图片缓存，前端通过JavaScript优化搜索交互和图片加载体验。新增README.md提供详细的部署和开发指南。

js/scripts.js

@@ -0,0 +1,105 @@
+document.addEventListener('DOMContentLoaded', function() {
+    const backToTop = document.getElementById('back-to-top');
+    const modal = document.getElementById('imagePreview');
+    const modalImg = document.getElementById('previewImage');
+    const closeBtn = document.getElementsByClassName('close')[0];
+    const searchInput = document.getElementById('searchInput');
+    const iconGrid = document.getElementById('iconGrid');
+
+    // 返回顶部按钮
+    window.onscroll = function() {
+        if (document.body.scrollTop > 20 || document.documentElement.scrollTop > 20) {
+            backToTop.style.display = 'block';
+        } else {
+            backToTop.style.display = 'none';
+        }
+    };
+
+    backToTop.onclick = function() {
+        window.scrollTo({
+            top: 0,
+            behavior: 'smooth'
+        });
+    };
+
+    // 图标预览模态框
+    document.querySelectorAll('.icon-image img').forEach(img => {
+        img.onclick = function() {
+            modal.style.display = 'block';
+            modalImg.src = this.getAttribute('data-high-res');
+            modalImg.alt = this.alt;
+        };
+    });
+
+    closeBtn.onclick = function() {
+        modal.style.display = 'none';
+    };
+
+    window.onclick = function(event) {
+        if (event.target == modal) {
+            modal.style.display = 'none';
+        }
+    };
+
+    // 搜索输入优化
+    // 搜索防抖功能
+    function debounce(func, wait) {
+        let timeout;
+        return function (...args) {
+            clearTimeout(timeout);
+            timeout = setTimeout(() => func.apply(this, args), wait);
+        };
+    }
+
+    document.addEventListener('DOMContentLoaded', function() {
+        const searchForm = document.getElementById('searchForm');
+        const searchInput = document.getElementById('searchInput');
+        
+        // 防止表单自动提交
+        searchForm.addEventListener('submit', function(e) {
+            e.preventDefault();
+            if (searchInput.value.trim()) {
+                this.submit();
+            }
+        });
+    
+        // 输入防抖
+        const debouncedSearch = debounce(function(value) {
+            if (value.trim().length >= 2) {
+                searchForm.submit();
+            }
+        }, 800);
+    
+        // 监听输入事件
+        searchInput.addEventListener('input', function(e) {
+            const value = e.target.value;
+            debouncedSearch(value);
+        });
+    
+        // 添加加载状态
+        searchForm.addEventListener('submit', function() {
+            const button = this.querySelector('button[type="submit"]');
+            button.innerHTML = '<i class="fas fa-spinner fa-spin"></i>';
+            button.disabled = true;
+            
+            // 2秒后恢复按钮状态（如果请求完成会被新页面覆盖）
+            setTimeout(() => {
+                button.innerHTML = '<i class="fas fa-search"></i>';
+                button.disabled = false;
+            }, 2000);
+        });
+    });
+
+    // 图标加载动画
+    const observer = new IntersectionObserver((entries) => {
+        entries.forEach(entry => {
+            if (entry.isIntersecting) {
+                entry.target.classList.add('fade-in');
+            }
+        });
+    });
+
+    document.querySelectorAll('.icon-card').forEach(card => {
+        observer.observe(card);
+    });
+});