fix(cluster): 停用的转发会在重启后自己复活 + 令牌轮转日志刷屏

从线上三节点（192.168.2.{30,106,60}）的日志里挖出四个问题，本轮修三个。

## 1. 停用的转发会复活（功能性缺陷，实测仍在发生）

线上现象：`minecraft` 在 store 里 disabled=1，worker 却仍在跑，今天
09:46 还在刷 `connect to local service [192.168.2.60:25565]: connection
refused` —— 对着一个用户刻意没启的本地服务死刷。同时三台 logs 里躺着
13956 / 3769 条 `proxy [x] already exists`，每 33 秒一轮。

四处叠加导致：
- stopForward 先读 link，再 SetLinkDisabled(true)，然后把**改之前**的
  副本交给 RevokeTask ⇒ published task 带 disabled=false（实测 id/flag
  都对不上：topology 里 link.id=223，store 里同一行是 199）
- ClaimFn **无条件** SetLinkDisabled(...,false)。原意是"重新认领时清掉
  停用标记"，但启动 reconcile 只要 worker 不在就重新 Claim ⇒ 每次重启
  都是"先清标记再起 worker"
- RevokeFn 停了 worker 却**没删 topology 条目**，条目活过 worker
- 于是下次重启 reconcile 看到"owned 但 worker 不在"→ 再次 Claim → 死循环

修法（把 disabled 的所有权交回两个用户动作）：
- Claim **只读** disabled 决定要不要起 worker；为 true 时连 topology
  条目一起摘掉，绝不复活
- 启动 reconcile 先按 store 跳过 disabled 的条目（省掉无谓的
  claim→skip 往返）
- RevokeFn 除停 worker 外，同时 RemoveTopologyEntry —— 撤销必须是
  完整退役，不能只是"停一下"
- stopForward 把 Disabled=true 随 task 发布出去，让持有该转发的节点
  即使本地 store 行陈旧也能判断这次停用是用户主动的

## 2. 令牌轮转日志零信息量却占满磁盘

每轮固定 3 行（OnToken cycle=N / forward cycle=N / token-send -> 200），
2 轮/秒，实测本机 **355 行/分钟、7 天 357 万行**，把真事件全淹了。
同一份信息（cycle / lastSync / roundDelayMs / 成员存活）本来就能从
GET /api/manager/cluster/ring 结构化拿到。

加 W4F_DEBUG 开关（沿用项目既有 W4F_ 前缀约定）：稳态三行降级为 debug、
默认关闭；**失败路径一律保留** —— 发送失败、陈旧令牌、非 2xx 正是别人
grep 的对象，静音它们是坏交易。实测同样 12 秒：36 行 → 4 行。

## 3. Link.ID 在 ReplaceLinks 之后必然失效

ReplaceLinks 是 DELETE + 重新 INSERT，sqlite 给每行**新的自增 id**。
任何在改写前捕获的 Link（典型：随 token 环跑的 Link）手里的 id 要么查无
此行，要么命中另一条转发 —— 实测捕获 alpha id=1，改写后新表是 3/4/5，
GetLink(1) 直接落空。

新增 LinkByTriple(local, remote, port) 按自然键查（业务代码本来就一律用
这个三元组标识转发），并把 claim/reconcile 切过去。查无行返回
(Link{}, false, nil) 而非 error：新建的转发没有行，应当照常启动。

## 4. homeagent_device 孤儿（已澄清，非独立缺陷）

它 disabled=1 且从不在 topology 里，是缺陷 1 的另一面（停用标记没进
token），随本次修复覆盖，无需单独处理。

## 测试

新增 4 个测试文件，重点是**验证测试本身抓得住 bug**：
- 临时回退 `ln.Disabled = true` 这行 → TestStopForwardPublishesDisabled-
  FlagInRevokeTask 如期变红，还原后变绿
- ⚠️ 第一版回归测试只断言 store 层，是**假绿**：newTestHandler 的 Ring
  为 nil，RevokeTask 那条（真正坏掉的）路根本没执行。补了带 ring 的
  newRingTestHandler，直接断言**发布出去的 task 上的 flag**
- LinkByTriple 在 ReplaceLinks 前后保持稳定；GetLink(id) 的失效被固化成
  一个可见的说明性测试
- 停用/start 往返、per-forward 停用不误伤兄弟转发
- 错误路径不静音、W4F_DEBUG 各种取值

go build / go vet / go test ./... 全绿，gofmt 干净。

internal/cluster/debug.go

@@ -0,0 +1,91 @@
+package cluster
+
+import (
+	"log"
+	"os"
+	"sync/atomic"
+)
+
+// logf is the package's logging seam: every cluster log line funnels through it
+// so the debug gate in debug.go has a single place to hook.
+func logf(format string, args ...any) { log.Printf(format, args...) }
+
+// Token rotation is the ring's heartbeat: with a 2s round delay it fires
+// continuously, and the default three log lines per round
+// ("OnToken cycle=N" / "forward cycle=N to X" / "token-send ... -> 200")
+// carry no information — no cycle number, address, timing or payload ever
+// changes in the steady state. Measured on the live 3-node cluster that was
+// ~510k lines/day on one node (3.5M lines in a week), which drowns every real
+// event in the journal and fills the disk for a signal that is already
+// available in structured form via GET /api/manager/cluster/ring (cycle,
+// lastSync, roundDelayMs, node aliveness).
+//
+// So the steady-state lines are demoted to a debug level, off by default and
+// enabled with W4F_DEBUG=token (or 1/all/true for every debug line). Failure
+// paths are NOT demoted: a send error, a stale token, a timeout or a leader
+// change is exactly what someone is grepping for, and losing those to a quiet
+// default would be a bad trade.
+const debugEnv = "W4F_DEBUG"
+
+// debugToken logs a per-token-round heartbeat line. Suppressed unless
+// W4F_DEBUG selects "token" (or a catch-all value).
+func debugToken(format string, args ...any) {
+	if debugTokenOn.Load() {
+		logf(format, args...)
+	}
+}
+
+// debugAll logs an ad-hoc diagnostic line. Suppressed unless W4F_DEBUG is set
+// to a catch-all value (1/all/true/*).
+func debugAll(format string, args ...any) {
+	if debugAllOn.Load() {
+		logf(format, args...)
+	}
+}
+
+var (
+	debugTokenOn atomic.Bool
+	debugAllOn   atomic.Bool
+)
+
+func init() { ReloadDebug() }
+
+// ReloadDebug re-reads W4F_DEBUG. Called once at init so tests can flip it
+// without restarting, and available at runtime for an operator who wants to
+// watch the ring without a redeploy.
+func ReloadDebug() {
+	v := os.Getenv(debugEnv)
+	switch normalized := normalizeDebugValue(v); normalized {
+	case "token":
+		debugTokenOn.Store(true)
+		debugAllOn.Store(false)
+	case "all":
+		debugTokenOn.Store(true)
+		debugAllOn.Store(true)
+	default:
+		debugTokenOn.Store(false)
+		debugAllOn.Store(false)
+	}
+}
+
+func normalizeDebugValue(v string) string {
+	// Compare case-insensitively without pulling in strings just for this.
+	out := make([]rune, 0, len(v))
+	for _, r := range v {
+		if r >= 'A' && r <= 'Z' {
+			r += 'a' - 'A'
+		}
+		out = append(out, r)
+	}
+	s := string(out)
+	switch s {
+	case "":
+		return ""
+	case "token", "tokens", "ring":
+		return "token"
+	}
+	// Any other non-empty value is a deliberate request for more output, so it
+	// is treated as a catch-all rather than silently muting the operator who
+	// set it. "0" lands here too: it was asked for, so honour it.
+	return "all"
+}

internal/cluster/debug_test.go

@@ -0,0 +1,108 @@
+package cluster
+
+import (
+	"bytes"
+	"log"
+	"os"
+	"strings"
+	"testing"
+)
+
+// captureLog redirects the standard logger into a buffer for the duration of
+// fn and returns what was written.
+func captureLog(t *testing.T, fn func()) string {
+	t.Helper()
+	var buf bytes.Buffer
+	orig := log.Writer()
+	origFlags := log.Flags()
+	log.SetOutput(&buf)
+	log.SetFlags(0)
+	defer func() {
+		log.SetOutput(orig)
+		log.SetFlags(origFlags)
+	}()
+	fn()
+	return buf.String()
+}
+
+func TestDebugTokenSuppressedByDefault(t *testing.T) {
+	os.Unsetenv(debugEnv)
+	ReloadDebug()
+
+	out := captureLog(t, func() {
+		debugToken("ring[%s] OnToken cycle=%d", "node:7500", 42)
+		debugToken("ring[%s] forward cycle=%d to %s", "node:7500", 42, "next:7500")
+		debugToken("token-send %s: size=%dB elapsed=%v -> %d", "next:7500", 5605, "170ms", 200)
+	})
+	if out != "" {
+		t.Fatalf("steady-state token lines logged with W4F_DEBUG unset: %q", out)
+	}
+}
+
+func TestDebugTokenEnabledByEnv(t *testing.T) {
+	for _, v := range []string{"token", "TOKEN", "tokens", "ring", "1", "true", "yes", "all", "*", "yes-please"} {
+		t.Run(v, func(t *testing.T) {
+			t.Setenv(debugEnv, v)
+			ReloadDebug()
+			if !debugTokenOn.Load() {
+				t.Fatalf("W4F_DEBUG=%q should enable the token heartbeat", v)
+			}
+			out := captureLog(t, func() {
+				debugToken("ring[%s] OnToken cycle=%d", "node:7500", 7)
+			})
+			if !strings.Contains(out, "OnToken cycle=7") {
+				t.Fatalf("W4F_DEBUG=%q: expected the line to be logged, got %q", v, out)
+			}
+		})
+	}
+}
+
+// The whole point of the gate is to shrink the journal, so the failure paths
+// must stay loud without any env var — losing a send error to a quiet default
+// would be a bad trade.
+func TestFailurePathsStayLoud(t *testing.T) {
+	os.Unsetenv(debugEnv)
+	ReloadDebug()
+
+	out := captureLog(t, func() {
+		logf("token-send %s: size=%dB elapsed=%v err=%v", "down:7500", 10, "5ms", "connection refused")
+	})
+	if !strings.Contains(out, "connection refused") {
+		t.Fatalf("send errors must never be gated: got %q", out)
+	}
+}
+
+func TestDebugAllOffForTokenOnly(t *testing.T) {
+	t.Setenv(debugEnv, "token")
+	ReloadDebug()
+	if !debugTokenOn.Load() {
+		t.Fatal("token level should enable debugToken")
+	}
+	if debugAllOn.Load() {
+		t.Fatal("token level must not enable the catch-all debugAll")
+	}
+	out := captureLog(t, func() { debugAll("scratch diagnostic") })
+	if out != "" {
+		t.Fatalf("debugAll should stay off at token level, got %q", out)
+	}
+}
+
+func TestNormalizeDebugValue(t *testing.T) {
+	cases := map[string]string{
+		"":         "",
+		"token":    "token",
+		"TOKEN":    "token",
+		"Ring":     "token",
+		"1":        "all",
+		"true":     "all",
+		"ALL":      "all",
+		"*":        "all",
+		"anything": "all", // unrecognised but deliberate → don't silence it
+		"0":        "all", // 0 is still a deliberate request for output
+	}
+	for in, want := range cases {
+		if got := normalizeDebugValue(in); got != want {
+			t.Errorf("normalizeDebugValue(%q) = %q, want %q", in, got, want)
+		}
+	}
+}

internal/cluster/ring_engine.go

@@ -182,7 +182,9 @@ func (e *Engine) OnToken(ctx context.Context, tk *Token) (*Token, error) {
 	if tk.SentAt > e.lastTokenAt {
 		e.lastTokenAt = tk.SentAt
 	}
-	log.Printf("ring[%s] OnToken cycle=%d", e.ID, tk.Cycle)
+	// Per-round heartbeat — steady state, no information. See debug.go: this
+	// fired ~2x/second and dominated the journal on every node.
+	debugToken("ring[%s] OnToken cycle=%d", e.ID, tk.Cycle)
 
 	// Parallel rhythm timer: operations run while the pace clock ticks.
 	// Delay scales with alive node count (more nodes → lower per-hop delay,
@@ -792,6 +794,14 @@ func (e *Engine) RemoveNode(nodeID string) *Task {
 	return e.state.AddRemoveNode(nodeID)
 }
 
+// RemoveTopologyEntry drops the active topology entry for a forward identified
+// by its natural key. Exposed so the app's claim path can retire an entry it
+// refuses to serve (see ClaimFn: a disabled forward must stop looking active,
+// otherwise the startup reconcile keeps re-claiming it on every restart).
+func (e *Engine) RemoveTopologyEntry(local, remote string, port int) bool {
+	return e.state.RemoveTopology(local, remote, port)
+}
+
 // RevokeTask publishes a revocation for an established forward through the
 // same token channel; the owning node stops the worker and drops topology.
 func (e *Engine) RevokeTask(local store.Local, remote store.Remote, link store.Link) *Task {

internal/cluster/ring_leader.go

@@ -128,7 +128,7 @@ func (e *Engine) forwardToNext(ctx context.Context, tk *Token) error {
 		if e.send == nil {
 			return nil
 		}
-		log.Printf("ring[%s] forward cycle=%d to %s", e.ID, tk.Cycle, next)
+		debugToken("ring[%s] forward cycle=%d to %s", e.ID, tk.Cycle, next)
 		err := e.send(ctx, next, tk)
 		if err == nil {
 			if e.state.LeaderID == e.ID {

internal/cluster/token_transport.go

@@ -8,7 +8,6 @@ import (
 	"context"
 	"encoding/json"
 	"fmt"
-	"log"
 	"net/http"
 	"time"
 )
@@ -52,11 +51,16 @@ func (t *TokenTransport) SendTo(getAddr func(nodeID string) string) func(ctx con
 		start := time.Now()
 		resp, err := cli.Do(req)
 		if err != nil {
-			log.Printf("token-send %s: size=%dB elapsed=%v err=%v", addr, len(body), time.Since(start).Round(time.Millisecond), err)
+			// NOT demoted: a failed send is the "neighbor offline" signal the
+			// ring's fault paths are diagnosed from.
+			logf("token-send %s: size=%dB elapsed=%v err=%v", addr, len(body), time.Since(start).Round(time.Millisecond), err)
 			return err
 		}
 		defer resp.Body.Close()
-		log.Printf("token-send %s: size=%dB elapsed=%v -> %d", addr, len(body), time.Since(start).Round(time.Millisecond), resp.StatusCode)
+		// Success path is a per-round heartbeat (size/elapsed/200 repeat
+		// verbatim every cycle) — debug only. The status-code check below stays
+		// loud on purpose, so a non-2xx still shows up without the debug flag.
+		debugToken("token-send %s: size=%dB elapsed=%v -> %d", addr, len(body), time.Since(start).Round(time.Millisecond), resp.StatusCode)
 		if resp.StatusCode >= 400 {
 			return fmt.Errorf("token POST %s -> HTTP %d", url, resp.StatusCode)
 		}