feat(guest): prune deleted bot from guest scope on removeBot

When a bot is deleted, prune its id from config.guestMode.bots (when an
array) and persist, mirroring the existing permissions.pruneBot(id)
member-access pruning. Thread CONFIG_PATH into BotManager so removeBot
can save the updated config.

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

src/index.ts

@@ -74,7 +74,8 @@ async function main() {
     config,
     logger,
     avatarStore,
-    permissions
+    permissions,
+    CONFIG_PATH
   );
   await botManager.loadSavedBots();