Clean duplicate dashboard status messages

Clean duplicate Status dashboard messages by marker, preserve the tracked message, and avoid full-channel purge on startup.

src/dashboard-message-cleanup.ts

@@ -0,0 +1,67 @@
+import { logger } from './logger.js';
+import type { Channel } from './types.js';
+
+const DASHBOARD_STATUS_MESSAGE_MARKER = '🤖 *모델 구성*';
+const DASHBOARD_DUPLICATE_CLEANUP_LIMIT = 100;
+
+function findDashboardCleanupChannel(opts: {
+  channels: Channel[];
+  statusChannelId: string;
+}): Channel | undefined {
+  if (!opts.statusChannelId) return undefined;
+  return opts.channels.find(
+    (item) =>
+      item.name.startsWith('discord') &&
+      item.isConnected() &&
+      item.deleteRecentMessagesByContent,
+  );
+}
+
+export async function purgeDashboardMessages(opts: {
+  channels: Channel[];
+  statusChannelId: string;
+}): Promise<number> {
+  const channel = findDashboardCleanupChannel(opts);
+  if (!channel?.deleteRecentMessagesByContent) return 0;
+
+  let total = 0;
+  for (let i = 0; i < 10; i += 1) {
+    const deleted = await channel.deleteRecentMessagesByContent(
+      `dc:${opts.statusChannelId}`,
+      {
+        contentIncludes: DASHBOARD_STATUS_MESSAGE_MARKER,
+        limit: DASHBOARD_DUPLICATE_CLEANUP_LIMIT,
+      },
+    );
+    total += deleted;
+    if (deleted < DASHBOARD_DUPLICATE_CLEANUP_LIMIT) break;
+  }
+  return total;
+}
+
+export async function cleanupDashboardDuplicateMessages(
+  opts: { channels: Channel[]; statusChannelId: string },
+  keepMessageId: string | null,
+): Promise<number> {
+  if (!opts.statusChannelId || !keepMessageId) return 0;
+
+  const channel = findDashboardCleanupChannel(opts);
+  if (!channel?.deleteRecentMessagesByContent) return 0;
+
+  try {
+    return await channel.deleteRecentMessagesByContent(
+      `dc:${opts.statusChannelId}`,
+      {
+        contentIncludes: DASHBOARD_STATUS_MESSAGE_MARKER,
+        exceptMessageId: keepMessageId,
+        limit: DASHBOARD_DUPLICATE_CLEANUP_LIMIT,
+      },
+    );
+  } catch (err) {
+    logger.warn(
+      { err, keepMessageId },
+      'Dashboard duplicate message cleanup failed',
+    );
+    return 0;
+  }
+}