feat(server): 按用户精确统计流量 — agent 改读 v2ray_api StatsService

节点 sing-box 编入 with_v2ray_api 后,每个 dp_uuid 有独立计数器
user>>>{dp_uuid}>>>traffic>>>uplink|downlink。agent 用 QueryStats(reset=true)
取窗口 delta,按用户精确上报(替代旧 clash 节点总量分摊:单用户准、多用户近似)。

- render.go: experimental.v2ray_api(loopback :19091)+ stats.users 列全部 dp_uuid
- v2rayapi/: vendor sing-box stats.pb.go(消息)+ 手写 client(用 v2ray 规范
  ServiceName 路径,绕开生成代码的 experimental.v2rayapi.* 误名)
- usage_v2ray.go: V2RayUsageSource,uplink/downlink 天然用户视角(无需 swap)
- agent.UseV2RayUsage() 取代 UseClashUsage();clash_api 保留作本地调试

节点需部署带 with_v2ray_api 的 sing-box(已编好 linux/amd64 二进制)。

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>

server/internal/agentd/render.go

@@ -12,12 +12,15 @@ import (
 // derived password (DeriveHy2Password) — both from the same dp_uuid source.
 //
 // Only the opaque dp_uuid is ever written; no account identity touches the node.
-// clash_api endpoint(loopback only)供 agent 读取节点累计流量做用量统计。
-// v2ray_api 未编入该 sing-box 构建、clash /connections 又不暴露用户,故只能
-// 取节点总量(downloadTotal/uploadTotal),由 agent 按当前 dp_uuid 归属/分摊。
+//
+// 用量统计走 v2ray_api StatsService(loopback gRPC):节点 sing-box 编入
+// with_v2ray_api,stats.users 列出全部 dp_uuid → 每个用户独立的
+// user>>>{dp_uuid}>>>traffic>>>uplink|downlink 计数器,agent 按用户精确读取
+// (替代旧的 clash 节点总量分摊)。clash_api 仍保留作本地调试。
 const (
 	clashAPIAddr   = "127.0.0.1:19090"
 	clashAPISecret = "pangolin-local-stats"
+	v2rayAPIAddr   = "127.0.0.1:19091"
 )
 
 func renderSingboxConfig(creds []Cred, reality *agentv1.RealityInbound, hy2 *agentv1.Hy2Inbound, deriveKey string) ([]byte, error) {
@@ -30,11 +33,35 @@ func renderSingboxConfig(creds []Cred, reality *agentv1.RealityInbound, hy2 *age
 				"external_controller": clashAPIAddr,
 				"secret":              clashAPISecret,
 			},
+			"v2ray_api": map[string]any{
+				"listen": v2rayAPIAddr,
+				"stats": map[string]any{
+					"enabled": true,
+					"users":   statsUsers(creds),
+				},
+			},
 		},
 	}
 	return json.MarshalIndent(cfg, "", "  ")
 }
 
+// statsUsers 收集所有去重 dp_uuid,供 v2ray_api stats.users 按用户开启流量计数器。
+func statsUsers(creds []Cred) []string {
+	seen := make(map[string]struct{}, len(creds))
+	users := make([]string, 0, len(creds))
+	for _, c := range creds {
+		if c.DpUUID == "" {
+			continue
+		}
+		if _, ok := seen[c.DpUUID]; ok {
+			continue
+		}
+		seen[c.DpUUID] = struct{}{}
+		users = append(users, c.DpUUID)
+	}
+	return users
+}
+
 func buildInbounds(creds []Cred, reality *agentv1.RealityInbound, hy2 *agentv1.Hy2Inbound, deriveKey string) []any {
 	inbounds := make([]any, 0, 2)