Move Discord bot token to service-specific environment

The Discord bot token environment variable has been relocated from the global to the service-specific environment section in docker-compose.yml. This ensures it is only available to the relevant service, improving security and configuration clarity.

docker-compose.yml

@@ -4,7 +4,6 @@ x-common-environment: &common-env
   ConnectionStrings__DefaultConnection: Server=postgres;Port=5432;Database=${POSTGRES_USER};Userid=${POSTGRES_USER};Password=${POSTGRES_PASSWORD};SslMode=Prefer;TrustServerCertificate=true
   Redis__ConnectionString: redis,ssl=false,name=${REDIS_NAME}
   ASPNETCORE_ENVIRONMENT: Production
-  Discord__BotToken: ${DISCORD_BOT_TOKEN}
 
 services:
   redis:
@@ -40,6 +39,7 @@ services:
     restart: always
     environment:
       <<: *common-env
+      Discord__BotToken: ${DISCORD_BOT_TOKEN}
       Discord__DevGuildId: ${DISCORD_DEV_GUILD}
       RunMigrations: ${BLINK_RUN_MIGRATIONS}
       WordsApiKey: ${WORDS_API_KEY}