fix: Remove bare SENTRY_DSN from environment sections

Bare variable references in environment: override env_file values
with the host shell value (empty). SENTRY_DSN is already loaded
via env_file: .env, so the explicit references were zeroing it out.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

docker-compose.yml

@@ -7,8 +7,6 @@ services:
     env_file: .env
     restart: unless-stopped
     network_mode: host
-    environment:
-      - SENTRY_DSN
 
   bot:
     build:
@@ -26,7 +24,6 @@ services:
       - MEMORY_SERVICE_URL=http://memory-service:8090
       - PORTAL_URL
       - BOT_API_KEY
-      - SENTRY_DSN
     volumes:
       - bot-data:/data
     depends_on: