fix(server/reward): 邀请发放审计 target 带对方 id(invite:reg:invitee=N 等,替换静态占位串)——审计可回答「因谁而发」

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

server/internal/reward/service.go

@@ -4,6 +4,7 @@ import (
 	"context"
 	"crypto/rand"
 	"database/sql"
+	"fmt"
 	"log/slog"
 	"sync"
 	"time"
@@ -110,11 +111,11 @@ func (s *Service) OnRegister(ctx context.Context, inviteeID int64, inviteCode, d
 		return // invitee 已绑定过(唯一约束)→ 放弃
 	}
 	if !rejected {
-		if _, _, err := s.g.GrantRewardTx(ctx, tx, inviterID, s.cfg.RegDays, "invite", "invite_reg_inviter", "ref-inviter"); err != nil {
+		if _, _, err := s.g.GrantRewardTx(ctx, tx, inviterID, s.cfg.RegDays, "invite", "invite_reg_inviter", fmt.Sprintf("invite:reg:invitee=%d", inviteeID)); err != nil {
 			slog.Warn("reward: grant inviter reg failed", "err", err)
 			return
 		}
-		if _, _, err := s.g.GrantRewardTx(ctx, tx, inviteeID, s.cfg.RegDays, "invite", "invite_reg_invitee", "ref-invitee"); err != nil {
+		if _, _, err := s.g.GrantRewardTx(ctx, tx, inviteeID, s.cfg.RegDays, "invite", "invite_reg_invitee", fmt.Sprintf("invite:reg:inviter=%d", inviterID)); err != nil {
 			slog.Warn("reward: grant invitee reg failed", "err", err)
 			return
 		}
@@ -135,10 +136,10 @@ func (s *Service) OnFirstPaidTx(ctx context.Context, tx *sql.Tx, inviteeID int64
 	if err != nil || !ok || status == "paid_rewarded" || status == "rejected" {
 		return err // 无邀请关系 / 已发过 / 被拒 → 不发
 	}
-	if _, _, err := s.g.GrantRewardTx(ctx, tx, inviterID, s.cfg.PaidDays, "invite", "invite_paid_inviter", "ref-paid-inviter"); err != nil {
+	if _, _, err := s.g.GrantRewardTx(ctx, tx, inviterID, s.cfg.PaidDays, "invite", "invite_paid_inviter", fmt.Sprintf("invite:paid:invitee=%d", inviteeID)); err != nil {
 		return err
 	}
-	if _, _, err := s.g.GrantRewardTx(ctx, tx, inviteeID, s.cfg.PaidDays, "invite", "invite_paid_invitee", "ref-paid-invitee"); err != nil {
+	if _, _, err := s.g.GrantRewardTx(ctx, tx, inviteeID, s.cfg.PaidDays, "invite", "invite_paid_invitee", fmt.Sprintf("invite:paid:inviter=%d", inviterID)); err != nil {
 		return err
 	}
 	return s.st.MarkPaidRewardedTx(ctx, tx, inviteeID, now)