feat: add restart: always to all Docker services

Docker will auto-restart all containers when Docker Desktop starts.
Combined with Docker Desktop's "start on login" setting, this ensures
all services survive macOS reboots without custom LaunchDaemons.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

backend/docker-compose.yml

@@ -1,6 +1,7 @@
 services:
   postgres:
     image: postgres:16-alpine
+    restart: always
     environment:
       POSTGRES_USER: dataviz
       POSTGRES_PASSWORD: dataviz_local
@@ -19,6 +20,7 @@ services:
       context: .
       dockerfile: services/data-service/Dockerfile
       network: host
+    restart: always
     ports:
       - "8001:8000"
     environment:
@@ -32,6 +34,7 @@ services:
       context: .
       dockerfile: services/chart-service/Dockerfile
       network: host
+    restart: always
     ports:
       - "8002:8000"
     environment:
@@ -48,6 +51,7 @@ services:
       context: .
       dockerfile: services/template-service/Dockerfile
       network: host
+    restart: always
     ports:
       - "8003:8000"
     environment:
@@ -61,6 +65,7 @@ services:
       context: .
       dockerfile: services/export-service/Dockerfile
       network: host
+    restart: always
     ports:
       - "8004:8000"
     environment: