增加 @提及、搜索筛选与找回密码，并将右栏热门改为正在聊。

补齐评论提及补全与通知、按作者/板块/仅标题搜索，以及邮箱验证码重置密码；同时修复 Go 提及正则并优化侧栏悬停样式。

Co-authored-by: Cursor <cursoragent@cursor.com>

service/mention.go

@@ -0,0 +1,65 @@
+package service
+
+import (
+	"regexp"
+	"strings"
+
+	"git.iioio.com/freefire/jiang13-forum/model"
+)
+
+const maxMentionsPerContent = 10
+
+// 与前端 highlightMentions 字符集对齐（字母数字下划线中文，兼容历史 -）
+// Go RE2 不支持 JS 的 \uXXXX，需用 \x{HHHH}
+var mentionPattern = regexp.MustCompile(`@([0-9A-Za-z_\x{4e00}-\x{9fa5}-]+)`)
+
+// ExtractMentionNames 从纯文本提取 @提及名（去重、保序）
+func ExtractMentionNames(text string) []string {
+	matches := mentionPattern.FindAllStringSubmatch(text, -1)
+	if len(matches) == 0 {
+		return nil
+	}
+	seen := make(map[string]struct{}, len(matches))
+	out := make([]string, 0, len(matches))
+	for _, m := range matches {
+		name := strings.TrimSpace(m[1])
+		if name == "" {
+			continue
+		}
+		key := strings.ToLower(name)
+		if _, ok := seen[key]; ok {
+			continue
+		}
+		seen[key] = struct{}{}
+		out = append(out, name)
+		if len(out) >= maxMentionsPerContent {
+			break
+		}
+	}
+	return out
+}
+
+// ResolveMentionUserIDs 将提及名解析为用户 ID（优先 username，其次 nickname；排除 excludeUserID）
+func ResolveMentionUserIDs(names []string, excludeUserID uint) []uint {
+	if len(names) == 0 {
+		return nil
+	}
+	ids := make([]uint, 0, len(names))
+	seen := make(map[uint]struct{}, len(names))
+	for _, name := range names {
+		var u model.User
+		err := model.DB.Select("id").Where("username = ?", name).First(&u).Error
+		if err != nil {
+			err = model.DB.Select("id").Where("nickname = ?", name).First(&u).Error
+		}
+		if err != nil || u.ID == 0 || u.ID == excludeUserID {
+			continue
+		}
+		if _, ok := seen[u.ID]; ok {
+			continue
+		}
+		seen[u.ID] = struct{}{}
+		ids = append(ids, u.ID)
+	}
+	return ids
+}