docs: put MinIO first-class on ground, add executive overview

Treat MinIO as existing stack infrastructure (default T3 warehouse, not
on the drone), add a one-page executive map, and record placement as an
open team question rather than a rip-and-replace.

docs/00-glossary.md

@@ -55,7 +55,7 @@ Terms and abbreviations used throughout this proposal.
 | **Docker Compose** | Declarative multi-container runtime; the only orchestrator on board a drone |
 | **k3s** | Lightweight Kubernetes distribution; used on the ground only |
 | **Dev Container** | Reproducible containerized development environment definition |
-| **MinIO** | S3-compatible object store; runs on-board for derived data and on the ground as the warehouse backend |
+| **MinIO** | S3-compatible object store **already in the stack**; default home is the **ground warehouse (T3)**. On-board use is an exception, not the baseline |
 | **Registry mirror** | Local copy of a container registry inside the air gap; drones pull images from it |
 | **OTA** | Over-the-air update — delivered before a mission while docked, never mid-flight |
 | **Fleet release manifest** | A versioned lockfile pinning every artifact (image digests, model weights, schemas, configs) that defines one fleet version |