Add Ground Zero map boundary

AGRARIAN_DEVELOPMENT_ROADMAP.md

@@ -470,7 +470,10 @@ Target deliverable: A small group can join a server, spawn into one biome, gathe
   controller, samples reachable wander points, projects chase/flee targets onto
   navmesh, requests server-authoritative AI movement when nav data exists, and
   retains direct movement fallback for early maps without nav data.
-- [ ] Add map boundaries or soft limits.
+- [x] Add map boundaries or soft limits. Added native
+  `AAgrarianMapBoundaryVolume`, placed `AGR_GroundZeroMapBoundary` around the
+  loaded 1 km Ground Zero tile, clamps server-authoritative player pawns back
+  inside the tile with padding, and exposes a warning-zone hook for later UI.
 - [ ] Add developer travel command.
 
 ## 0.1.E Inventory System