feat(distributed): 支持单主控多节点部署和停服迁移

复用现有 k3s 调度和 Job 生命周期，增加 worker 接入与批准、受保护节点身份、归档传输、持久迁移锁及活动 PVC 切换；同步管理员 API、CLI、面板和隔离规则。分布式模式默认关闭，保持单机兼容。

验证：Go 全量测试与 vet；面板 874 个测试、lint/build；Linux VM 安装器测试、清单服务端 dry-run、网络命名空间防火墙实测。A/B/C 三机 WireGuard、Velocity 和迁移验收仍待完成。

deploy/crd/felis.lolicon.best_minecraftservers.yaml

@@ -281,6 +281,8 @@ spec:
               storage:
                 description: Storage configures the world PVC.
                 properties:
+                  claimName:
+                    type: string
                   size:
                     description: Size is the requested PVC capacity (e.g. "10Gi").
                     type: string
@@ -289,6 +291,8 @@ spec:
                       uses the default.
                     type: string
                 type: object
+              nodeName:
+                type: string
               subdomain:
                 description: |-
                   Subdomain is the per-server label under the deployment zone. It is the
@@ -301,6 +305,8 @@ spec:
           status:
             description: MinecraftServerStatus is the observed state (spec §4 status.*).
             properties:
+              nodeName:
+                type: string
               autoRestarts:
                 description: |-
                   AutoRestarts counts how often the operator recreated the pod of a start