fix: add pgdata volume for persistence + fix seed path

docker-compose.yml

@@ -7,11 +7,13 @@ services:
       POSTGRES_DB: servesync
       POSTGRES_USER: servesync
       POSTGRES_PASSWORD: servesync
+    volumes:
+      - pgdata:/var/lib/postgresql/data
     healthcheck:
       test: ["CMD-SHELL", "pg_isready -U servesync"]
       interval: 5s
       timeout: 5s
-      retries: 5
+      retries: 10
 
   redis:
     image: redis:7-alpine
@@ -47,3 +49,6 @@ services:
       - backend
       - frontend
     restart: unless-stopped
+
+volumes:
+  pgdata: