feat: per-forward worker 模型 — 每条转发独立 frpc 配置+独立进程

核心改动（ring 协议不变，Task 本来就是 {Local,Remote,Link} 三元组）:
- process.WorkerKey: worker 键改为 'local~remote~port' 三元组
- renderForward: 每条 forward 渲染只含 1 个 proxy 的独立 frpc 配置
  (替代 renderRemote 把该 remote 全部 forwards 塞进一个进程)
- ClaimFn/RevokeFn: 认领/撤销只操作这一条 forward 自己的进程
- SyncWorkers/auto-start: 只拉起 localOnly 转发的独立进程,
  集群转发由 ring 认领节点拉起 (消除三台争抢 proxy already exists)
- RemoteStatus/StartRemote/StopRemote/RestartRemote: remote 级聚合辅助,
  保持 /profiles API 形状不变, 前端零改动
- handleStatus/logs: 按 worker key 解析真实 remote 名

效果: 三台节点的 frpc 各自只注册自己拥有的 proxy, 单条转发故障不再波及兄弟

internal/httpapi/handlers_forwards.go

@@ -4,6 +4,7 @@ import (
 	"encoding/json"
 	"net/http"
 
+	"webui4frpc/internal/process"
 	"webui4frpc/internal/store"
 )
 
@@ -74,10 +75,11 @@ func (h *Handler) startForward(local, remote string, port int) error {
 	ln.Disabled = false
 	if loc.LocalOnly {
 		if h.Process != nil {
-			if _, has := h.Process.Status(remote); has {
-				_ = h.Process.Restart(remote)
+			key := process.WorkerKey(local, remote, port)
+			if _, has := h.Process.Status(key); has {
+				_ = h.Process.Restart(key)
 			} else {
-				_ = h.Process.Start(remote)
+				_ = h.Process.Start(key)
 			}
 		}
 		return nil
@@ -109,8 +111,9 @@ func (h *Handler) stopForward(local, remote string, port int) error {
 	}
 	if loc.LocalOnly {
 		if h.Process != nil {
-			if _, has := h.Process.Status(remote); has {
-				_ = h.Process.Restart(remote)
+			key := process.WorkerKey(local, remote, port)
+			if _, has := h.Process.Status(key); has {
+				_ = h.Process.Restart(key)
 			}
 		}
 		return nil