minio: declare region eu-west, don't leave it as live-only drift

serves.s3-bucket.region still said us-east-1 (PR #58 already fixed this,
unmerged) while the live mesh-minio sidecar had MESH_MINIO_REGION=eu-west
set out-of-band, not in the manifest at all — and the actual minio server
had no region configured whatsoever (mc admin config get region: empty),
apparently lost across a container recreation since nothing declared it.
Every s3-bucket consumer binding ${bound:s3-bucket:region} was reading
the stale us-east-1 declaration regardless of what was actually live.

Declares MINIO_REGION on the server container and MESH_MINIO_REGION on
the sidecar, matching the static serves declaration, so this is mesh-
managed and durable rather than a manual mc admin config or docker env
override that the next recreation silently drops.

modules/minio/module.json

@@ -25,7 +25,7 @@
   "serves": {
     "s3-bucket": {
       "scheme": "http",
-      "region": "us-east-1",
+      "region": "eu-west",
       "port": 9000
     }
   },
@@ -99,7 +99,8 @@
         "/var/lib/minio/root.secret:/run/secrets/root:ro"
       ],
       "env": {
-        "MINIO_ROOT_PASSWORD_FILE": "/run/secrets/root"
+        "MINIO_ROOT_PASSWORD_FILE": "/run/secrets/root",
+        "MINIO_REGION": "eu-west"
       }
     },
     {
@@ -116,6 +117,7 @@
         "MESH_MINIO_ENDPOINT": "http://minio:9000",
         "MESH_MINIO_ROOT_USER": "meshroot",
         "MESH_MINIO_ROOT_PASSWORD_FILE": "/run/secrets/root",
+        "MESH_MINIO_REGION": "eu-west",
         "MESH_BROKER_FILE": "/run/secrets/broker",
         "MESH_RECEIVES": "/var/lib/minio/grants/mesh.json"
       },