Fix backend startup: add retry logic for DB init, proper logging, ensure all models imported before create_all, increase healthcheck start_period

docker-compose.yml

@@ -10,6 +10,7 @@ services:
       interval: 30s
       timeout: 10s
       retries: 3
+      start_period: 10s
 
   backend:
     build: ./backend
@@ -27,9 +28,10 @@ services:
         condition: service_healthy
     healthcheck:
       test: ["CMD", "curl", "-f", "http://localhost:8000/api/health"]
-      interval: 30s
-      timeout: 10s
-      retries: 3
+      interval: 10s
+      timeout: 5s
+      retries: 10
+      start_period: 30s
 
   db:
     image: postgres:16-alpine
@@ -45,6 +47,7 @@ services:
       interval: 5s
       timeout: 5s
       retries: 5
+      start_period: 10s
 
 volumes:
   fitness_db_data: