```

feat(js): 改进图片下载功能并添加文件名处理

- 添加downloadFilenameSerial变量用于生成唯一的下载文件名序列号
- 实现getImageExtension函数来根据content-type获取正确的文件扩展名
- 创建buildImageFilename函数来构建安全的文件名，支持从URL解析原始名称
- 实现buildDownloadProxyUrl函数来构建下载代理URL
- 重构downloadImage函数，增加错误处理和进度提示
- 添加静默下载选项，避免批量下载时重复显示提示
- 改进批量下载逻辑，统计成功和失败数量并显示相应提示
- 增强文件名安全性，过滤特殊字符和路径遍历字符
```

static/js/main.js

@@ -78,6 +78,7 @@ let currentGeneratedUrls = [];
 let currentMode = 'trial'; // 'trial' 或 'key'
 let uploadedFiles = []; // 存储当前待上传的参考图
 let isSetterActive = false; // 是否激活了拍摄角度设置器模式
+let downloadFilenameSerial = 0;
 
 function switchMode(mode) {
     currentMode = mode;
@@ -104,23 +105,92 @@ function switchMode(mode) {
     updateCostPreview(); // 切换模式时同步计费预览
 }
 
-async function downloadImage(url) {
+function getImageExtension(contentType) {
+    const type = (contentType || '').split(';')[0].trim().toLowerCase();
+    const extensionMap = {
+        'image/jpeg': 'jpg',
+        'image/jpg': 'jpg',
+        'image/png': 'png',
+        'image/webp': 'webp',
+        'image/gif': 'gif',
+        'image/bmp': 'bmp',
+        'image/avif': 'avif'
+    };
+    return extensionMap[type] || 'png';
+}
+
+function buildImageFilename(url, contentType = '') {
+    downloadFilenameSerial += 1;
+    const fallbackName = `ai-vision-image-${Date.now()}-${downloadFilenameSerial}.${getImageExtension(contentType)}`;
+
     try {
-        const response = await fetch(url);
+        const parsed = new URL(url, window.location.href);
+        const rawName = decodeURIComponent(parsed.pathname.split('/').filter(Boolean).pop() || '');
+        const safeName = rawName
+            .replace(/[\\/:*?"<>|]/g, '_')
+            .replace(/[^\x20-\x7E]/g, '_')
+            .replace(/\s+/g, '_');
+        const extMatch = safeName.match(/\.(png|jpe?g|webp|gif|bmp|avif)$/i);
+
+        if (!extMatch) return fallbackName;
+
+        const ext = extMatch[0].toLowerCase();
+        const baseName = safeName
+            .slice(0, safeName.length - ext.length)
+            .replace(/^\.+|\.+$/g, '')
+            .slice(0, 80) || 'ai-vision-image';
+
+        return `${baseName}${ext}`;
+    } catch (e) {
+        return fallbackName;
+    }
+}
+
+function buildDownloadProxyUrl(url, filename) {
+    const params = new URLSearchParams();
+    params.set('url', url);
+    params.set('filename', filename);
+    return `/api/download_proxy?${params.toString()}`;
+}
+
+async function downloadImage(url, options = {}) {
+    if (!url) return false;
+
+    const silent = options.silent === true;
+
+    try {
+        if (!silent) showToast('正在准备下载...', 'info');
+
+        const filenameHint = buildImageFilename(url);
+        const response = await fetch(buildDownloadProxyUrl(url, filenameHint), {
+            credentials: 'same-origin'
+        });
+
+        if (!response.ok) {
+            let message = `HTTP ${response.status}`;
+            const responseType = response.headers.get('Content-Type') || '';
+            if (responseType.includes('application/json')) {
+                const data = await response.json();
+                message = data.error || message;
+            }
+            throw new Error(message);
+        }
+
         const blob = await response.blob();
+        const filename = buildImageFilename(url, blob.type);
         const blobUrl = window.URL.createObjectURL(blob);
         const a = document.createElement('a');
         a.href = blobUrl;
-        // 从 URL 提取文件名
-        const filename = url.split('/').pop().split('?')[0] || 'ai-vision-image.png';
         a.download = filename;
         document.body.appendChild(a);
         a.click();
         document.body.removeChild(a);
-        window.URL.revokeObjectURL(blobUrl);
+        setTimeout(() => window.URL.revokeObjectURL(blobUrl), 1000);
+        return true;
     } catch (e) {
         console.error('下载失败:', e);
-        showToast('下载失败，请尝试右键保存', 'error');
+        if (!silent) showToast('下载失败，请稍后重试', 'error');
+        return false;
     }
 }
 
@@ -246,11 +316,20 @@ async function init() {
         downloadAllBtn.onclick = async () => {
             if (currentGeneratedUrls.length === 0) return;
             showToast(`正在准备下载 ${currentGeneratedUrls.length} 张作品...`, 'info');
+            let successCount = 0;
             for (const url of currentGeneratedUrls) {
-                await downloadImage(url);
+                const ok = await downloadImage(url, { silent: true });
+                if (ok) successCount += 1;
                 // 稍微延迟一下，防止浏览器拦截
                 await new Promise(r => setTimeout(r, 300));
             }
+
+            const failedCount = currentGeneratedUrls.length - successCount;
+            if (failedCount === 0) {
+                showToast('下载已开始，请留意浏览器下载列表', 'success');
+            } else {
+                showToast(`${failedCount} 张下载失败，请稍后重试`, 'error');
+            }
         };
     }