feat(channels): 流控可配 —— 陌生人私聊额度走账号配置 directMsgPerMin（裁决 13）

- 后端：账号顶层 directMsgPerMin（缺失/0 = 保护性默认 6 条/分；正值 = 该值；负值 = 关闭并留带 source 的 WARN）
- 日志如实报出**实际生效**额度（adapter.(*FlowGate).DirectPerMin()），告警文案不再写死 6
- 面板：渠道配置表单加字段（含帮助文案）+ 回显/写回链路（LIMIT_KEYS 四键）+ 账号卡片摘要
- 文案纠错：AdapterConfigSummary 的 msgPerMin 由「私聊每分钟上限」改为「非主人消息每分钟总上限」（原描述是误导），并列补 directMsgPerMin 行
- 变异实测：缺键丢默认 / 负值当 1 条每分 / 前端吞负值 —— 三个都精确打红并还原
- ⚠️ 已知缺口（下一片补，gateway 面）：GET/PUT /admin/channels 尚未下发/解码该键 ⇒ 面板暂时回显空、保存会把 -1 重置为 0

cmd/cyrene/channels.go

@@ -176,16 +176,17 @@ type namedAdapter struct {
 	denyUsers   []string
 	// 流控限制（design/12 §6 策略三/四）。它们始终经 Config() 暴露，使桥能构建按账号
 	// 的入口闸门；桥把零值默认映射为保护性取值，把负值映射为「关闭」。
-	groupMsgPerMin int
-	msgPerMin      int
-	maxMessages    int
+	groupMsgPerMin  int
+	directMsgPerMin int
+	msgPerMin       int
+	maxMessages     int
 }
 
 func (n *namedAdapter) Name() string { return n.name }
 
 func (n *namedAdapter) Config() map[string]any {
 	cfg := n.PlatformAdapter.Config()
-	out := make(map[string]any, len(cfg)+7)
+	out := make(map[string]any, len(cfg)+8)
 	for k, v := range cfg {
 		out[k] = v
 	}
@@ -194,6 +195,7 @@ func (n *namedAdapter) Config() map[string]any {
 	out["allowUsers"] = n.allowUsers
 	out["denyUsers"] = n.denyUsers
 	out["groupMsgPerMin"] = n.groupMsgPerMin
+	out["directMsgPerMin"] = n.directMsgPerMin
 	out["msgPerMin"] = n.msgPerMin
 	out["maxMessages"] = n.maxMessages
 	return out
@@ -282,6 +284,7 @@ func buildAccountAdapter(platform string, acct config.ChannelAccount, log *slog.
 		allowUsers:      acct.AllowUsers,
 		denyUsers:       acct.DenyUsers,
 		groupMsgPerMin:  acct.GroupMsgPerMin,
+		directMsgPerMin: acct.DirectMsgPerMin,
 		msgPerMin:       acct.MsgPerMin,
 		maxMessages:     acct.MaxMessages,
 	}, nil

cmd/cyrene/channels_test.go

@@ -118,7 +118,7 @@ func hasAdapter(adapters []adapter.PlatformAdapter, name string) bool {
 // save → Reload path uses exactly this builder.
 func TestChannelFactoryBuildFromFile(t *testing.T) {
 	path := filepath.Join(t.TempDir(), "channels.json")
-	if err := os.WriteFile(path, []byte(`{"kook":[{"id":"conf0","config":{"bot_token":"bt"},"denyGroups":["g-1"],"allowUsers":["u-1"],"groupMsgPerMin":3}]}`), 0o600); err != nil {
+	if err := os.WriteFile(path, []byte(`{"kook":[{"id":"conf0","config":{"bot_token":"bt"},"denyGroups":["g-1"],"allowUsers":["u-1"],"groupMsgPerMin":3,"directMsgPerMin":-1}]}`), 0o600); err != nil {
 		t.Fatalf("write channels.json: %v", err)
 	}
 	f := &channelFactory{path: path, fallback: channelAccountsFromEnv(), log: testLog()}
@@ -146,6 +146,11 @@ func TestChannelFactoryBuildFromFile(t *testing.T) {
 		if got, _ := cfg["groupMsgPerMin"].(int); got != 3 {
 			t.Errorf("groupMsgPerMin = %v, want 3", cfg["groupMsgPerMin"])
 		}
+		// directMsgPerMin 同一条链：channels.json 的账号顶层字段 → namedAdapter.Config() →
+		// 桥的 gateOptions。断桥这一环就等于「面板/文件配了却没人读」（负值必须原样透出）。
+		if got, _ := cfg["directMsgPerMin"].(int); got != -1 {
+			t.Errorf("directMsgPerMin = %v, want -1", cfg["directMsgPerMin"])
+		}
 	}
 }