fix(infra): use SSD volume for MinIO storage

Switch MinIO from Docker VM storage to external SSD volume
at /Volumes/TillJakob-S04/ManaData/minio for better performance.

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

docker-compose.macmini.yml

@@ -59,7 +59,7 @@ services:
       MINIO_ROOT_USER: ${MINIO_ACCESS_KEY:-minioadmin}
       MINIO_ROOT_PASSWORD: ${MINIO_SECRET_KEY:-minioadmin}
     volumes:
-      - minio_data:/data
+      - minio-ssd-data:/data
     ports:
       - "9000:9000"
       - "9001:9001"
@@ -1288,8 +1288,8 @@ volumes:
     name: mana-postgres-data
   redis_data:
     name: mana-redis-data
-  minio_data:
-    name: mana-minio-data
+  minio-ssd-data:
+    external: true  # Bound to /Volumes/TillJakob-S04/ManaData/minio
   victoriametrics_data:
     name: mana-victoria-data
   grafana_data: