docs: establish simulation architecture gate

docs/PROJECT_CONTEXT.md

@@ -2,9 +2,11 @@
 
 > Agent-facing context for understanding the project quickly.
 >
-> Snapshot basis: repository state after commit `b8752f8`, July 2026. Treat the
+> Snapshot basis: repository state after commit `0900022`, July 2026. Treat the
 > code as the source of truth when this document and the implementation differ.
 
+See the [documentation map](README.md) for the authority and scope of each plan.
+
 ## Quick orientation
 
 **The Steward** is currently a small Godot prototype for an embodied village
@@ -358,9 +360,11 @@ creation, and some gameplay API responsibilities.
 `WorldViewManager` bridges simulation data to visible NPC nodes. It:
 
 - instantiates `NpcVisual` scenes;
-- maps task strings to world markers;
+- resolves resource nodes, random wander targets, and remaining activity
+  markers;
+- writes the selected ResourceNode ID onto the NPC as a transitional behavior;
 - sends targets to visuals;
-- reports arrival back to `SimulationManager`;
+- reports arrival and navigation failure back to `SimulationManager`;
 - applies visual death state.
 
 ### `player/npc/NpcVisual.gd`
@@ -376,7 +380,8 @@ creation, and some gameplay API responsibilities.
 ### `player/player.gd` and `player/camera_rig.gd`
 
 These implement camera-relative character movement, physical interaction
-proximity checks, mouse capture, and the elevated follow camera.
+proximity checks, ResourceNode harvesting, mouse capture, and the elevated
+follow camera.
 
 ### `world/ui/ui.gd`
 
@@ -500,6 +505,26 @@ Use four conceptual layers:
 Do not make the simulation core depend on `Node3D`, scene paths, animation,
 physics frames, or a currently loaded map.
 
+The authoritative-boundary decision is recorded in
+[ADR 0001](decisions/0001-simulation-authority-boundary.md). The current
+`ResourceNode` state and `WorldViewManager` target selection are transitional,
+not patterns to extend into inventories, schedules, or relationships.
+
+### Authority and active-world adapters
+
+Persistent mutable state belongs in versioned, serializable simulation records.
+Systems mutate those records. Godot nodes:
+
+- present nearby records;
+- expose active-world interaction transforms and navigation results;
+- translate player input into simulation commands;
+- synchronize active position through an explicit adapter;
+- never become the only owner of a persistent amount, reservation, action, or
+  identity.
+
+Target selection may consume facts supplied by the active world, but the
+presentation bridge must not author an NPC's decision or persistent target.
+
 ### Stable identity
 
 Every persistent entity should eventually have a stable ID:
@@ -649,14 +674,25 @@ The project has two interleaved tracks.
 Every major systems milestone should produce a shareable visual behavior. Every
 visual milestone should support or reveal actual simulation state.
 
-## Immediate milestone: the simulation garden
+## Immediate milestone: scaffold, architecture gate, then simulation garden
 
-Before integrating Terrain3D into the playable runtime, migrate food and wood
-from abstract zones to finite resource nodes on the current flat test map. This
-keeps target-selection and resource-conservation debugging separate from terrain
-and navigation changes.
+Food and wood migration on the flat test map is complete. The next visual step
+is a deliberately minimal `JajceWorld` scaffold, greybox, navigation spike, and
+resource-placement proof. Do not proceed directly from that proof into
+open-ended beauty production.
 
-The next coherent visual slice should then aim for:
+After the scaffold proves terrain and navigation, complete the architecture
+gate:
+
+- deterministic clock and controlled random source;
+- fixed-seed headless scenarios with final-state checksums;
+- versioned serializable NPC, village, and resource state;
+- data-defined action and profession IDs;
+- separated action selection, execution, target resolution, and visual travel;
+- resource amount and reservation authority moved out of scene nodes;
+- explicit synchronization of active NPC position.
+
+The coherent visual slice can then aim for:
 
 - one attractive valley section;
 - six named villagers;
@@ -713,6 +749,8 @@ These remain part of the vision, not the next implementation target.
 11. Use Conventional Commits.
 12. Update these documents when a decision materially changes the vision,
     architecture, milestones, or current-state description.
+13. Follow the authority order in [the documentation map](README.md); do not
+    let a focused visual or migration plan silently redefine system ownership.
 
 ## Definition of “reusable for the future game”