docs: define distributed Mission Core topology

docs/01_IMPLEMENTATION_PLAN.md

@@ -127,7 +127,9 @@ still stops and seals only local reception and reports scanner state as unknown.
 The Polygon branch follows
 [`docs/12_SIMULATION_POLYGON_PRODUCT_AND_SRS.md`](12_SIMULATION_POLYGON_PRODUCT_AND_SRS.md)
 and
-[`ADR 0015`](adr/0015-simulation-polygon-qualification-boundary.md).
+[`ADR 0015`](adr/0015-simulation-polygon-qualification-boundary.md). Component
+placement and field/offline topology follow
+[`ADR 0016`](adr/0016-distributed-product-edge-and-worker-topology.md).
 It does not reorder or weaken the K1 physical-evidence gates in this document.
 Its first gate, SIM S0, is accepted:
 
@@ -175,6 +177,14 @@ virtual-only authority boundary. A shared operator-facing deployment still
 requires a reviewed read-only D mount/source configuration; UI-0 does not use
 SSH as a product data plane.
 
+Mission Core remains a distributed web product. React is served by a long-lived
+Gateway/API and renders canonical state through browser-native components.
+Gazebo/PX4/ROS 2/Nav2 run headless on a registered Linux simulation worker; the
+native Gazebo GUI is optional worker-local diagnostics. A future field vehicle
+runs a headless Linux Edge Agent with local-first evidence and store-and-forward
+synchronization. The browser never talks directly to PX4, and field
+execution/failsafe cannot depend on a browser or WAN connection.
+
 ## Stage 0 — repository and host baseline
 
 Deliverables: