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/ratelimit.go

@@ -0,0 +1,88 @@
+package service
+
+import (
+	"sync"
+	"time"
+)
+
+// RateLimiter 简单内存限流器，防止重复刷屏
+type RateLimiter struct {
+	mu       sync.Mutex
+	records  map[string][]time.Time
+	settings *ForumSettingsService
+}
+
+func NewRateLimiter(settings *ForumSettingsService) *RateLimiter {
+	r := &RateLimiter{
+		records:  make(map[string][]time.Time),
+		settings: settings,
+	}
+	go r.cleanup()
+	return r
+}
+
+// Allow 检查 action+key 是否允许操作
+func (r *RateLimiter) Allow(action, key string) bool {
+	limit := r.limitFor(action)
+	window := r.windowFor(action)
+	if limit <= 0 {
+		return true
+	}
+	fullKey := action + ":" + key
+
+	r.mu.Lock()
+	defer r.mu.Unlock()
+	now := time.Now()
+	cutoff := now.Add(-window)
+	times := r.records[fullKey]
+	var valid []time.Time
+	for _, t := range times {
+		if t.After(cutoff) {
+			valid = append(valid, t)
+		}
+	}
+	if len(valid) >= limit {
+		r.records[fullKey] = valid
+		return false
+	}
+	valid = append(valid, now)
+	r.records[fullKey] = valid
+	return true
+}
+
+func (r *RateLimiter) limitFor(action string) int {
+	if action == "friend_link" {
+		return 5
+	}
+	return r.settings.RateLimitFor(action)
+}
+
+func (r *RateLimiter) windowFor(action string) time.Duration {
+	if action == "friend_link" {
+		return time.Hour
+	}
+	return time.Duration(r.settings.RateLimitWindowSec()) * time.Second
+}
+
+func (r *RateLimiter) cleanup() {
+	ticker := time.NewTicker(5 * time.Minute)
+	for range ticker.C {
+		r.mu.Lock()
+		// 使用最大窗口清理，覆盖友链 1 小时窗口
+		cutoff := time.Now().Add(-time.Hour * 2)
+		for k, times := range r.records {
+			var valid []time.Time
+			for _, t := range times {
+				if t.After(cutoff) {
+					valid = append(valid, t)
+				}
+			}
+			if len(valid) == 0 {
+				delete(r.records, k)
+			} else {
+				r.records[k] = valid
+			}
+		}
+		r.mu.Unlock()
+	}
+}