增加BotStageEvent事件定义，以及其两个子类型BotRegisteredEvent、BotStartedEvent的定义

simbot-api/src/commonMain/kotlin/love/forte/simbot/event/BotStageEvent.kt

@@ -0,0 +1,55 @@
+/*
+ *     Copyright (c) 2024. ForteScarlet.
+ *
+ *     Project    https://github.com/simple-robot/simpler-robot
+ *     Email      [email protected]
+ *
+ *     This file is part of the Simple Robot Library (Alias: simple-robot, simbot, etc.).
+ *
+ *     This program is free software: you can redistribute it and/or modify
+ *     it under the terms of the GNU Lesser General Public License as published by
+ *     the Free Software Foundation, either version 3 of the License, or
+ *     (at your option) any later version.
+ *
+ *     This program is distributed in the hope that it will be useful,
+ *     but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *     Lesser GNU General Public License for more details.
+ *
+ *     You should have received a copy of the Lesser GNU General Public License
+ *     along with this program.  If not, see <https://www.gnu.org/licenses/>.
+ *
+ */
+
+package love.forte.simbot.event
+
+import love.forte.simbot.bot.Bot
+import love.forte.simbot.bot.BotManager
+
+
+/**
+ * 与 Bot 相关的阶段性事件。
+ * 例如bot被注册了、bot被启动了。
+ *
+ * @author ForteScarlet
+ */
+public interface BotStageEvent : BotEvent {
+    /**
+     * 相关的 bot.
+     */
+    override val bot: Bot
+}
+
+/**
+ * 当一个 Bot 已经在某个 [BotManager] 中被注册后的事件。
+ *
+ * @author ForteScarlet
+ */
+public interface BotRegisteredEvent : BotStageEvent
+
+/**
+ * 当一个 Bot **首次** 启动成功后的事件。
+ *
+ * @author ForteScarlet
+ */
+public interface BotStartedEvent : BotStageEvent