refactor: Gitea 式目录改组，移除本分支 SPA 与杂项产物

将 model/service/handler/middleware 迁至 models/services/routers/api/modules/auth，并删除 frontend、embed_static、scripts 及误入库缓存/二进制。

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

services/common.go

@@ -0,0 +1,155 @@
+package service
+
+import (
+	"errors"
+	"fmt"
+	"net/mail"
+	"strings"
+	"sync"
+	"unicode"
+	"unicode/utf8"
+
+	"golang.org/x/crypto/bcrypt"
+)
+
+var (
+	ErrUserExists            = errors.New("用户名已存在")
+	ErrEmailExists           = errors.New("邮箱已被注册")
+	ErrInvalidCred           = errors.New("用户名或密码错误")
+	ErrUserBanned            = errors.New("账号已被禁言")
+	ErrWeakPassword          = errors.New("密码至少 6 位")
+	ErrInvalidUsername       = errors.New("用户名 2-32 位，支持中文、字母、数字与下划线")
+	ErrInvalidEmail          = errors.New("邮箱格式不正确")
+	ErrPostNotFound          = errors.New("帖子不存在")
+	ErrCommentNotFound       = errors.New("评论不存在")
+	ErrPermissionDenied      = errors.New("无权操作")
+	ErrBoardNotFound         = errors.New("板块不存在")
+	ErrPostEditLocked        = errors.New("帖子已被管理员锁定，无法编辑")
+	ErrPostCommentsLocked    = errors.New("该帖子已锁定讨论，无法评论")
+	ErrPostEditExpired       = errors.New("已超过可编辑时限")
+	ErrRevisionNotFound      = errors.New("历史版本不存在")
+	ErrInvalidSetting        = errors.New("无效的设置值")
+	ErrSearchKeywordTooShort = errors.New("搜索关键词过短")
+	ErrSearchKeywordTooLong  = errors.New("搜索关键词过长")
+	ErrPostTitleTooLong      = errors.New("标题过长")
+	ErrPostTagsTooLong       = errors.New("标签过长")
+	ErrPostContentTooLong    = errors.New("正文过长")
+	ErrCommentTooLong        = errors.New("评论内容过长")
+	ErrCaptchaInvalid        = errors.New("验证码错误或已过期")
+	ErrEmailCodeInvalid      = errors.New("邮箱验证码错误或已过期")
+	ErrEmailCodeCooldown     = errors.New("发送过于频繁，请稍后再试")
+	ErrMailNotConfigured     = errors.New("邮件服务未配置或未启用")
+	ErrRegisterClosed        = errors.New("论坛暂未开放注册，请联系管理员配置邮件服务")
+)
+
+// HashPassword 使用 bcrypt 加密密码
+func HashPassword(password string) (string, error) {
+	bytes, err := bcrypt.GenerateFromPassword([]byte(password), bcrypt.DefaultCost)
+	return string(bytes), err
+}
+
+// CheckPassword 校验密码
+func CheckPassword(hash, password string) bool {
+	return bcrypt.CompareHashAndPassword([]byte(hash), []byte(password)) == nil
+}
+
+// ValidateUsername 校验用户名：中文/字母/数字/下划线，2-32 个字符
+func ValidateUsername(username string) error {
+	n := utf8.RuneCountInString(username)
+	if n < 2 || n > 32 {
+		return ErrInvalidUsername
+	}
+	for _, r := range username {
+		if unicode.IsLetter(r) || unicode.IsDigit(r) || r == '_' {
+			continue
+		}
+		return ErrInvalidUsername
+	}
+	return nil
+}
+
+// NormalizeEmail 规范化邮箱（小写去空格）
+func NormalizeEmail(email string) string {
+	return strings.ToLower(strings.TrimSpace(email))
+}
+
+// ValidateEmail 校验邮箱格式
+func ValidateEmail(email string) error {
+	email = NormalizeEmail(email)
+	if email == "" {
+		return ErrInvalidEmail
+	}
+	addr, err := mail.ParseAddress(email)
+	if err != nil || addr.Address != email {
+		return ErrInvalidEmail
+	}
+	return nil
+}
+
+// ValidatePassword 校验密码强度
+func ValidatePassword(password string, minLen int) error {
+	if minLen <= 0 {
+		minLen = 6
+	}
+	if utf8.RuneCountInString(password) < minLen {
+		return fmt.Errorf("密码至少 %d 位", minLen)
+	}
+	return nil
+}
+
+// SensitiveFilter 敏感词过滤器
+type SensitiveFilter struct {
+	mu    sync.RWMutex
+	words []string
+}
+
+func NewSensitiveFilter() *SensitiveFilter {
+	return &SensitiveFilter{
+		words: []string{"违禁词示例", "广告刷单"},
+	}
+}
+
+// LoadFromFile 从配置文件加载敏感词，每行一个词
+func (f *SensitiveFilter) LoadFromFile(path string) {
+	data, err := osReadFile(path)
+	if err != nil {
+		return
+	}
+	lines := strings.Split(string(data), "\n")
+	var words []string
+	for _, line := range lines {
+		line = strings.TrimSpace(line)
+		if line != "" && !strings.HasPrefix(line, "#") {
+			words = append(words, line)
+		}
+	}
+	if len(words) > 0 {
+		f.mu.Lock()
+		f.words = words
+		f.mu.Unlock()
+	}
+}
+
+func (f *SensitiveFilter) Filter(text string) string {
+	f.mu.RLock()
+	defer f.mu.RUnlock()
+	result := text
+	for _, w := range f.words {
+		if w == "" {
+			continue
+		}
+		replacement := strings.Repeat("*", utf8.RuneCountInString(w))
+		result = strings.ReplaceAll(result, w, replacement)
+	}
+	return result
+}
+
+// osReadFile 避免循环依赖，简单封装
+func osReadFile(path string) ([]byte, error) {
+	return readFile(path)
+}
+
+// readFile 由 filter_io.go 实现
+var readFile = func(path string) ([]byte, error) {
+	return nil, errors.New("not implemented")
+}