fix(bots): intercept /confess so original never hits chat

Root cause of "not anonymous":
1. Confess deleted via raw SQL with no MESSAGE_DELETE broadcast
2. Frontend extractIds only accepted message_id, but deletes send id
   so live clients never removed deleted messages without refresh

Fix:
- Intercept /confess at message create: never store or broadcast the
  original; post only the anonymous bot message
- Accept both id and message_id on MESSAGE_DELETE in the WS store
- Include both fields on delete broadcasts

web/src/stores/ws.ts

@@ -52,9 +52,17 @@ function isRecord(value: unknown): value is Record<string, unknown> {
 }
 
 function extractIds(payload: UnknownPayload | undefined): { channel_id?: string; conversation_id?: string; message_id: string } | null {
-  if (!payload || typeof payload.message_id !== 'string') return null;
-  if (typeof payload.channel_id === 'string') return { channel_id: payload.channel_id, message_id: payload.message_id };
-  if (typeof payload.conversation_id === 'string') return { conversation_id: payload.conversation_id, message_id: payload.message_id };
+  if (!payload) return null;
+  // Backend MESSAGE_DELETE uses "id"; some other events use "message_id".
+  const messageId =
+    typeof payload.message_id === 'string'
+      ? payload.message_id
+      : typeof payload.id === 'string'
+        ? payload.id
+        : null;
+  if (!messageId) return null;
+  if (typeof payload.channel_id === 'string') return { channel_id: payload.channel_id, message_id: messageId };
+  if (typeof payload.conversation_id === 'string') return { conversation_id: payload.conversation_id, message_id: messageId };
   return null;
 }