fix(头像生成): 当邮箱为空时使用昵称生成头像哈希

修复 getCravatar 函数在邮箱为空时无法生成有效头像的问题。现在当邮箱为空或不存在时，函数会尝试使用昵称作为替代标识符生成 MD5 哈希。如果两者都不可用，则返回默认占位符头像，确保始终返回有效的头像 URL。

cwd-api/src/api/admin/listComments.ts

@@ -65,7 +65,7 @@ export const listComments = async (c: Context<{ Bindings: Bindings }>) => {
 					? row.likes
 					: 0,
 			ua: row.ua,
-			avatar: await getCravatar(row.email, avatarPrefix || undefined),
+			avatar: await getCravatar(row.email, row.name, avatarPrefix || undefined),
 			isAdmin: adminEmail && row.email === adminEmail
 		}))
 	);

cwd-api/src/api/public/getComments.ts

@@ -69,7 +69,7 @@ export const getComments = async (c: Context<{ Bindings: Bindings }>) => {
     // 2. 批量处理头像并格式化
     const allComments = await Promise.all(results.map(async (row: any) => ({
       ...row,
-      avatar: await getCravatar(row.email, avatar_prefix || undefined),
+      avatar: await getCravatar(row.email, row.name, avatar_prefix || undefined),
       isAdmin: adminEmail && row.email === adminEmail,
       replies: []
     })))

cwd-api/src/utils/getAvatar.ts

@@ -4,16 +4,38 @@
 const DEFAULT_AVATAR_PREFIX = 'https://gravatar.com/avatar';
 
 /**
- * 辅助函数：生成 gravatar.com 头像地址 (MD5 算法)
- * @param email - 邮箱地址
- * @param prefix - 头像服务前缀，默认为 https://gravatar.com/avatar
+ * 当缺少邮箱或邮箱为空时使用的占位 hash
+ * 32 个 0，符合 MD5 长度要求，Gravatar 会回退到默认头像样式
  */
-export const getCravatar = async (email: string, prefix?: string): Promise<string> => {
-  const cleanEmail = email.trim().toLowerCase();
-  const msgUint8 = new TextEncoder().encode(cleanEmail);
-  const hashBuffer = await crypto.subtle.digest('MD5', msgUint8);
-  const hashArray = Array.from(new Uint8Array(hashBuffer));
-  const hashHex = hashArray.map(b => b.toString(16).padStart(2, '0')).join('');
-  const avatarPrefix = prefix || DEFAULT_AVATAR_PREFIX;
-  return `${avatarPrefix}/${hashHex}?s=200&d=retro`;
-};
+const DEFAULT_AVATAR_HASH = '00000000000000000000000000000000';
+
+/**
+ * 辅助函数：生成 gravatar.com 头像地址 (MD5 算法)
+ * 优先使用邮箱；当邮箱不存在或为空时，使用昵称计算 MD5。
+ */
+export const getCravatar = async (
+	email: string | null | undefined,
+	name?: string | null | undefined,
+	prefix?: string
+): Promise<string> => {
+	const avatarPrefix = prefix || DEFAULT_AVATAR_PREFIX;
+
+	const pickIdentifier = (value: string | null | undefined) => {
+		if (!value || typeof value !== 'string') return null;
+		const trimmed = value.trim().toLowerCase();
+		return trimmed || null;
+	};
+
+	const identifier = pickIdentifier(email) || pickIdentifier(name);
+
+	if (!identifier) {
+		return `${avatarPrefix}/${DEFAULT_AVATAR_HASH}?s=200&d=retro`;
+	}
+
+	const msgUint8 = new TextEncoder().encode(identifier);
+	const hashBuffer = await crypto.subtle.digest('MD5', msgUint8);
+	const hashArray = Array.from(new Uint8Array(hashBuffer));
+	const hashHex = hashArray.map((b) => b.toString(16).padStart(2, '0')).join('');
+
+	return `${avatarPrefix}/${hashHex}?s=200&d=retro`;
+};