fix: add .dockerignore and env_file to docker-compose

Prevents .env from being baked into Docker image (was overriding
config defaults). Adds env_file directive so containers load host
.env properly.

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

docker-compose.yml

@@ -36,6 +36,7 @@ services:
       - full  # Only start with: docker compose --profile full up -d
     ports:
       - "8001:8000"  # Use 8001 to avoid conflict with local dev server
+    env_file: .env
     environment:
       DATABASE_URL: postgresql://orion_user:secure_password@db:5432/orion_db
       JWT_SECRET_KEY: ${JWT_SECRET_KEY:-your-super-secret-key}
@@ -62,6 +63,7 @@ services:
     profiles:
       - full  # Only start with: docker compose --profile full up -d
     command: celery -A app.core.celery_config worker --loglevel=info -Q default,long_running,scheduled
+    env_file: .env
     environment:
       DATABASE_URL: postgresql://orion_user:secure_password@db:5432/orion_db
       REDIS_URL: redis://redis:6379/0