fix: verify-server.sh exit on first check, bump flower/beat to 256m

- Remove set -e so script continues through all checks
- Use POSIX arithmetic to avoid exit code 1 from (( ))
- Bump flower and celery-beat mem_limit from 128m to 256m (OOM killed)

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

docker-compose.yml

@@ -107,7 +107,7 @@ services:
     depends_on:
       redis:
         condition: service_healthy
-    mem_limit: 128m
+    mem_limit: 256m
     healthcheck:
       disable: true
     networks:
@@ -128,7 +128,7 @@ services:
     depends_on:
       redis:
         condition: service_healthy
-    mem_limit: 128m
+    mem_limit: 256m
     healthcheck:
       test: ["CMD-SHELL", "curl -f http://localhost:5555/ || exit 1"]
       interval: 30s