docs(deployment): update memory limits and celery concurrency across all guides

Sync all deployment docs with actual docker-compose.yml values:
- celery-worker: 512→768MB, concurrency 4→2
- db: 512→256MB, celery-beat: 256→128MB, flower: 256→192MB
- Redis maxmemory: 256mb→100mb (matches container mem_limit 128m)
- Add redis-exporter to scaling guide memory budget

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

docs/deployment/docker.md

@@ -94,11 +94,10 @@ services:
   celery:
     build: .
     restart: always
-    command: celery -A app.celery worker --loglevel=info --concurrency=4
+    command: celery -A app.core.celery_config worker --loglevel=info -Q default,long_running,scheduled
     environment:
       DATABASE_URL: postgresql://orion_user:${DB_PASSWORD}@db:5432/orion_db
       REDIS_URL: redis://redis:6379/0
-      CELERY_BROKER_URL: redis://redis:6379/1
     env_file:
       - .env
     depends_on:
@@ -109,7 +108,7 @@ services:
     deploy:
       resources:
         limits:
-          memory: 512M
+          memory: 768M
 
   celery-beat:
     build: .
@@ -148,7 +147,7 @@ services:
   redis:
     image: redis:7-alpine
     restart: always
-    command: redis-server --appendonly yes --maxmemory 256mb --maxmemory-policy allkeys-lru
+    command: redis-server --maxmemory 100mb --maxmemory-policy allkeys-lru
     volumes:
       - redis_data:/data
     healthcheck: