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-executive.md

@@ -0,0 +1,61 @@
+# 00 — Executive overview
+
+A one-page map of the proposal. Details and trade-offs live in the linked docs.
+Nothing here is a mandate: it is a from-scratch platform sketch the team can
+reshape once real constraints are on the table.
+
+## Goal
+
+Build an **on-prem, air-gapped data platform** for an autonomous drone swarm:
+accumulate sensor and detection data on each unit, share only what peers need in
+flight, and offload complete flights to a ground warehouse for replay and
+training.
+
+## Constraints (given)
+
+- No internet / no external access in flight; data stays inside the system.
+- Each drone is autonomous; mesh links are intermittent — **no swarm-wide orchestrator**.
+- On-board today: **Docker Compose**, **DuckDB**, YOLO-like video analytics; **Parquet** under evaluation.
+- **MinIO is already in the stack** — exact placement not fully known yet (see below).
+- Ground side can run lightweight Kubernetes; this proposal keeps k3s **on the ground only**.
+
+## Data contract (proposed)
+
+| What | Where | Crosses the air? |
+| --- | --- | --- |
+| Raw telemetry | Local NVMe (Parquet / Hive layout) | **No** — offloads after landing |
+| Pose / detections (derived) | Local store + peer pub/sub | **Yes** — small, budgeted |
+| Full flight archive | Ground warehouse (Parquet + object store) | After landing only |
+
+One layout on every floor so offload is a **mirror**, not a migration
+([03 — Data platform](03-data-platform.md)).
+
+## Sync rule
+
+1. **Fast path:** compact pose frames (~45 B @ 5 Hz) + event-shaped detections.
+2. **Bulk path (peers):** sealed derived partitions when the link allows
+   (rsync/SSH proposed; alternatives open).
+3. **Never** push raw high-rate telemetry peer-to-peer in flight.
+
+## MinIO (first-class, placement TBD)
+
+MinIO is treated as **already chosen infrastructure**, not something to rip out.
+
+| Role | Stance in this sketch |
+| --- | --- |
+| **Ground warehouse (T3)** | **Primary home** — S3 API under the Parquet lake / offload target |
+| **On-board (drone)** | **Default: no** — competes with flight-critical CPU/RAM; local Parquet + DuckDB is enough for the hot path |
+| **On-board exception** | Not excluded if a team already relies on an S3 API in Compose; then derived-only, never the 5 Hz pose path |
+| **5 Hz pose / collision state** | **Not MinIO** — pub/sub (UDP in the PoC; Zenoh proposed) |
+| **Inter-drone history catch-up** | Prefer pull of sealed partitions (SSH/rsync); MinIO replication only if ops already standardised on it |
+
+Open item for the team: document how MinIO is used today, then lock T2/T3 roles
+([09 — Open questions](09-open-questions.md)).
+
+## What to read next
+
+1. [12 — Design journey](12-design-journey.md) — narrative + deep links into code  
+2. [Implemented vs proposed](../README.md#implemented-now-vs-proposed-next) — PoC vs production intent  
+3. [09 — Open questions](09-open-questions.md) — including MinIO placement  
+
+Live visual PoC: [swarm.produktor.io](https://swarm.produktor.io/) (same access as this repository).