fix: preserve Telegram topic (message_thread_id) in sub-agent announcements

When native slash commands are executed in Telegram topics/forums, the
originating topic context was not being preserved. This caused sub-agent
announcements to be delivered to the wrong topic.

Root cause: Native slash command context did not set OriginatingChannel
and OriginatingTo, causing session delivery context to fallback to the
user's personal ID instead of the group ID + topic.

Fix: Added OriginatingChannel and OriginatingTo to native slash command
context, ensuring topic information is preserved for sub-agent announcements.

Related session fields:
- lastThreadId: preserved via MessageThreadId
- lastTo: now correctly set to group ID via OriginatingTo
- deliveryContext: includes threadId for proper routing

src/telegram/bot-native-commands.ts

@@ -311,6 +311,9 @@ export const registerTelegramNativeCommands = ({
             CommandTargetSessionKey: route.sessionKey,
             MessageThreadId: resolvedThreadId,
             IsForum: isForum,
+            // Originating context for sub-agent announce routing
+            OriginatingChannel: "telegram" as const,
+            OriginatingTo: `telegram:${chatId}`,
           });
 
           const disableBlockStreaming =