新增Discord消息发送功能，支持通过频道ID或名称发送消息，并添加相应的错误提示

core/src/main/java/com/xujiayao/discord_mc_chat/server/discord/DiscordManager.java

@@ -6,6 +6,7 @@ import com.xujiayao.discord_mc_chat.utils.config.ModeManager;
 import com.xujiayao.discord_mc_chat.utils.i18n.I18nManager;
 import net.dv8tion.jda.api.JDA;
 import net.dv8tion.jda.api.JDABuilder;
+import net.dv8tion.jda.api.entities.channel.concrete.TextChannel;
 import net.dv8tion.jda.api.interactions.commands.Command;
 import net.dv8tion.jda.api.interactions.commands.build.CommandData;
 import net.dv8tion.jda.api.interactions.commands.build.Commands;
@@ -113,6 +114,50 @@ public class DiscordManager {
 		return false;
 	}
 
+	/**
+	 * Sends a message to a Discord channel.
+	 *
+	 * @param channelIdentifier The ID or Name of the channel.
+	 * @param content           The message content.
+	 */
+	public static void sendMessage(String channelIdentifier, String content) {
+		TextChannel channel = getTextChannel(channelIdentifier);
+		if (channel != null) {
+			channel.sendMessage(content).queue();
+		}
+	}
+
+	/**
+	 * Retrieves a TextChannel by its ID or name.
+	 *
+	 * @param identifier The ID or name of the channel.
+	 * @return The TextChannel if found, null otherwise.
+	 */
+	private static TextChannel getTextChannel(String identifier) {
+		TextChannel tc;
+
+		// Try search by name
+		// Return first result. Use with caution if multiple channels have the same name.
+		List<TextChannel> channels = jda.getTextChannelsByName(identifier, true);
+		if (!channels.isEmpty()) {
+			tc = channels.getFirst();
+		} else {
+			// Try parsing as ID
+			tc = jda.getTextChannelById(identifier);
+			if (tc == null) {
+				LOGGER.error("discord.manager.channel_not_found", identifier);
+				return null;
+			}
+		}
+
+		if (!tc.canTalk()) {
+			LOGGER.error("discord.manager.channel_cannot_talk", identifier);
+			return null;
+		}
+
+		return tc;
+	}
+
 	/**
 	 * Shuts down the Discord bot.
 	 */

core/src/main/resources/lang/en_us.yml

@@ -54,6 +54,8 @@ discord:
     registering_commands: "Registering Discord DMCC commands. This may take a while... (should be within 1 minute)"
     commands_success: "Discord DMCC commands registered successfully!"
     commands_failed: "Failed to register Discord DMCC commands."
+    channel_not_found: "Discord text channel not found: \"{}\""
+    channel_cannot_talk: "Cannot send messages in Discord text channel: \"{}\""
   command:
     reply_failed: "Failed to send reply message to Discord command sender."
     reply_failed_detail: "This is expected behavior for reload/shutdown commands."

core/src/main/resources/lang/zh_cn.yml

@@ -54,6 +54,8 @@ discord:
     registering_commands: "正在注册 Discord DMCC 命令。这可能需要一段时间...（理应在 1 分钟以内）"
     commands_success: "Discord DMCC 命令注册成功！"
     commands_failed: "注册 Discord DMCC 命令失败。"
+    channel_not_found: "未找到 Discord 文字频道：\"{}\""
+    channel_cannot_talk: "无法在 Discord 文字频道中发送消息：\"{}\""
   command:
     reply_failed: "无法向 Discord 命令发送者发送回复消息。"
     reply_failed_detail: "对于 reload/shutdown 命令，这是预期的行为。"