fix: 登录频率限制 bug — lock_until=0 导致计数被清零

根因: 初始 lock_until=0 时 now >= 0 + 60 恒为真, 每次请求都清除计数
修复: lock_until 改用 None 表示未锁定, 仅非 None 时做过期判断

Co-Authored-By: Claude <noreply@anthropic.com>

config/plugins/commands.yaml

@@ -9,6 +9,10 @@ commands:
     permissions:
     - framework.scaffold.plugin
     source: internal
+  echo: &id001
+    description: echo input
+    permissions: []
+    source: plugin.example_plugin
   help:
     description: 显示帮助信息
     permissions:
@@ -19,6 +23,11 @@ commands:
     permissions:
     - framework.command.history.read
     source: internal
+  install:
+    description: '从在线索引安装插件: install <name> 或 install --list'
+    permissions:
+    - framework.plugin.install
+    source: internal
   netdiag:
     description: 网络服务诊断
     permissions:
@@ -29,6 +38,10 @@ commands:
     permissions:
     - framework.permission.read
     source: internal
+  plugin_status: &id002
+    description: show status
+    permissions: []
+    source: plugin.example_plugin
   pm_plugin_status:
     description: '权限管理: 查看插件权限状态'
     permissions:
@@ -84,6 +97,9 @@ commands:
     permissions:
     - framework.command.test
     source: internal
-last_updated: 1742.472300949
-plugin_commands: {}
-total_commands: 17
+last_updated: 11552.003166269
+plugin_commands:
+  example_plugin:
+    echo: *id001
+    plugin_status: *id002
+total_commands: 20