chore: v0.1.1 — 版本号收拢进 internal/version + 发布脚本校验和覆盖安装包

- 新增 internal/version 包作为版本号唯一来源，release.sh 通过
  -ldflags -X 注入真实 tag。此前 /api/manager/status 与集群 JoinInfo
  里各自硬编码 "0.1.0"，产物报告的版本与 tag 无关。
- release.sh：SHA256SUMS 移到原生安装包构建之后统一重算，覆盖
  deb/rpm/setup.exe/pkg。此前只算 tar.gz/zip，用户校验安装包会得到
  "no file was verified"（v0.1.0 发布时实际踩到）。
- rpm spec / build_installers.sh 默认版本与 changelog、README 安装
  示例文件名同步到 0.1.1。

验证：go test ./internal/cluster/... ./internal/httpapi/... 通过；
6 平台产物架构逐个 file 校验正确；linux-amd64 实跑 /status 报告
version=0.1.1（确认 ldflags 注入生效）。

cmd/webui4frpc/main.go

@@ -25,6 +25,7 @@ import (
 	"webui4frpc/internal/process"
 	"webui4frpc/internal/render"
 	"webui4frpc/internal/store"
+	"webui4frpc/internal/version"
 )
 
 func main() {
@@ -132,7 +133,7 @@ func main() {
 	}
 	var ring *cluster.Engine
 	ring = cluster.NewEngine(
-		selfID, selfID, *user, *pass, "0.1.0", nil,
+		selfID, selfID, *user, *pass, version.Version, nil,
 		&cluster.AppHandler{
 			LoadFn: func() (float64, float64) {
 				// NetPct: real NIC saturation from /proc/net/dev deltas vs
@@ -533,7 +534,7 @@ func main() {
 // CreateCluster so the node is at least functional as standalone.
 func retryJoinCluster(ctx context.Context, ring *cluster.Engine, targetAddr, joinKey string) {
 	selfNode := ring.State().Nodes[0]
-	ji := cluster.JoinInfo{ID: selfNode.ID, Addr: selfNode.Addr, Version: "0.1.0", JoinKey: joinKey}
+	ji := cluster.JoinInfo{ID: selfNode.ID, Addr: selfNode.Addr, Version: version.Version, JoinKey: joinKey}
 	deadline := time.NewTimer(5 * time.Minute)
 	defer deadline.Stop()
 	ticker := time.NewTicker(10 * time.Second)
@@ -593,7 +594,7 @@ func retryRejoinCached(ctx context.Context, ring *cluster.Engine, peersJSON stri
 			return
 		}
 		for _, p := range peers {
-			ji := cluster.JoinInfo{ID: selfNode.ID, Addr: selfNode.Addr, Version: "0.1.0", JoinKey: p.Key}
+			ji := cluster.JoinInfo{ID: selfNode.ID, Addr: selfNode.Addr, Version: version.Version, JoinKey: p.Key}
 			jc, cancel := context.WithTimeout(ctx, 8*time.Second)
 			err := ring.JoinRing(jc, p.Addr, ji)
 			cancel()