Drop the last references to the bot's code living in this repo

switchToClone no longer tries to carry bot/app across a clone, and the compose comment, STATUS row,
README and the plan doc all describe the installed-release model instead.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

docker-compose.yml

@@ -199,7 +199,7 @@ services:
       start_period: 30s
     restart: unless-stopped
 
-  # ---------------------------------------------------------------- Discord bot (python; code lives in ./bot/app)
+  # ------------------------------------------- Discord bot (python; its release is installed in /srv/bot/app)
   discord-bot:
     logging: *vglog
     labels: { vanguard.service: discord-bot, vanguard.category: bot }