docs: SSH-based bulk sync and peer queries, spatial extension

Replace object-store replication with rsync over persistent multiplexed
SSH (ed25519, pinned known_hosts, forced commands as the only remote
API); demote GraphQL to the ground integration standard. Add DuckDB
spatial extension for separation audits, perimeter predicates and
trajectory analysis in the local planar frame.

docs/02-architecture.md

@@ -55,8 +55,8 @@ graph TB
 
 - The **event hook** is the on-board "lambda": when the writer lands new *derived* rows (state, detections), it triggers registered actions — broadcast, MinIO upload, or a local mission-logic callback. Nothing polls.
 - The **state publisher** broadcasts compact position/attitude/detection payloads over the mesh pub/sub (transport analysis in [04 — Swarm sync](04-swarm-sync.md)).
-- **MinIO** holds derived datasets only, replicated opportunistically between drones.
-- The **query API** answers ad-hoc peer requests against local DuckDB (the query standard is also in [04](04-swarm-sync.md)).
+- **Bulk sync** pulls sealed derived partitions from peers over persistent SSH (rsync delta transfer); MinIO remains optional where an S3 API is wanted.
+- **Peer queries** run against local DuckDB via SSH forced commands — allow-listed query templates, columnar responses (the standard is in [04](04-swarm-sync.md)).
 
 ## Communication planes