docs: update architecture gate progress

BUILD_IN_PUBLIC_PLAN.md:
- Mark systems gate items deterministic clock and headless checksum
  as complete; remaining gate work stays flagged as in-progress
- Rename TaskZone references to ActivityMarkers for consistency

LEARNING_ROADMAP.md:
- Add architecture gate progress note: first deterministic slice
  (SimulationClock, seeded streams, headless checksum) is implemented
- Update recommended implementation order to reflect shifted priorities

PROJECT_CONTEXT.md:
- Note that farm and forest markers have been deleted from main.tscn
- Update activity marker description (4 remaining: guard/study/rest/food)
- Add SimulationClock.gd and deterministic_simulation_test.gd to repo map
- Update technical debt: randomness is now seeded but RNG state is not
  yet serialized; clock is explicit but orchestration still lives on scene tree
- Gate status updated with completed first-slice summary

RESOURCE_NODE_MIGRATION.md:
- Mark Phase 4b (player parity) complete
- Phase 6 renamed from 'remove zone model' to 'replace activity markers'
  with progress note: TaskZone container and FarmZone/ForestZone deleted
- Update divergences to note farm/forest scene nodes have been removed

docs/BUILD_IN_PUBLIC_PLAN.md

@@ -41,7 +41,8 @@ Do not redo these tasks:
 - hunger, energy, starvation, death, task scoring, and task duration;
 - task-change and village-change signals;
 - visual NPC navigation and arrival reporting;
-- farm, forest, food, guard, study, and rest markers;
+- finite berry/tree ResourceNodes plus food, guard, study, and rest activity
+  markers;
 - aggregate village UI;
 - initial tree assets;
 - a baked navigation region for the current flat test area.
@@ -61,7 +62,7 @@ Main
 ├── SimulationManager
 ├── WorldViewManager
 ├── ActiveNPCs
-├── TaskZone markers
+├── ActivityMarkers
 ├── WorldEnvironment
 └── UI
 ```
@@ -93,7 +94,7 @@ Main
 │   │   └── ResourceNodes
 │   │       ├── BerryBush instances
 │   │       └── Tree instances
-│   ├── LegacyTaskMarkers              temporary non-resource activities
+│   ├── LegacyActivityMarkers          temporary non-resource activities
 │   │   ├── FoodZone
 │   │   ├── GuardZone
 │   │   ├── StudyZone
@@ -290,7 +291,7 @@ Create `world/jajce/JajceWorld.tscn` with:
 - placeholder `VillageRoot`;
 - placeholder `FoliageRoot`;
 - a navigation region;
-- resource-node containers plus temporary fallback markers;
+- resource-node containers plus temporary activity markers;
 - lighting and environment.
 
 Create `JajceLookdev.tscn` that instances `JajceWorld` and adds a temporary
@@ -351,14 +352,14 @@ river, and waterfall silhouettes plus a temporary baked navigation loop. The
 Terrain3D seed remains flat; sculpt refinement and the final bake resume only
 after the architecture gate.
 
-### Systems gate — Harden simulation authority ⏭ next
+### Systems gate — Harden simulation authority 🔶 in progress
 
 After the scaffold, greybox, and navigation spike prove the world shape, pause
 visual production and complete the mandatory architecture gate from the
 learning roadmap:
 
-- deterministic clock and seeded randomness;
+- deterministic clock and seeded randomness; ✅
-- fixed-seed headless scenarios and final-state checksum;
+- fixed-seed headless scenarios and final-state checksum; ✅
 - versioned serializable NPC, village, and resource records;
 - resource amount and reservation authority outside scene nodes;
 - stable action/profession IDs and initial definitions;
@@ -406,7 +407,7 @@ Once the world composition is stable:
 3. Place or move bushes and trees under
    `JajceWorld/WorldObjects/ResourceNodes` while preserving stable IDs.
 4. Reconnect only remaining non-resource activity markers under
-   `JajceWorld/LegacyTaskMarkers`.
+   `JajceWorld/LegacyActivityMarkers`.
 5. Bake navigation for the new walkable area.
 6. Test each existing task from multiple spawn positions.
 7. Verify task arrival still transitions from traveling to working.

docs/LEARNING_ROADMAP.md

@@ -54,6 +54,18 @@ The gate is complete when the same scenario produces the same checksum without
 loading `main.tscn`, and loading or unloading a visual does not change
 authoritative NPC or resource state.
 
+**Current progress:** the first deterministic slice is implemented:
+
+- `SimulationClock` advances explicit fixed ticks while preserving remainder;
+- NPC decisions and visual wander requests use controlled per-NPC random
+  streams derived from an exported simulation seed;
+- a headless scenario verifies same-seed equality, different-seed divergence,
+  and a final-state checksum without loading `main.tscn`.
+
+The gate remains open. Versioned state records, scene-independent resource
+authority, stable definitions, responsibility separation, and visual
+load/unload invariance are still required.
+
 ## Three vertical slices
 
 The long-term vision contains three major risks. Validate them separately before
@@ -599,8 +611,8 @@ Completed foundations:
 
 The practical next sequence is:
 
-1. Begin the architecture gate with deterministic clock/randomness, a headless
+1. Add versioned serializable NPC, village, and resource state records,
-   scenario runner, final-state checksums, and serializable state records.
+   including enough clock and RNG state for deterministic continuation.
 2. Move resource amount/reservation authority out of `ResourceNode` scenes.
 3. Replace free-form task and profession strings with stable IDs and
    definitions.

docs/PROJECT_CONTEXT.md

@@ -180,8 +180,9 @@ The current prototype implements a very early version of observe, autonomous
 task choice, physical travel, work completion, resource change, and direct
 player assistance. NPC `gather_food` and `gather_wood` tasks now use finite
 world `ResourceNode` instances (berry bushes and trees) rather than abstract
-zone markers. The zone markers remain only for player interaction and
+zone markers. The obsolete farm and forest markers have been removed. Separate
-non-resource tasks. The migration is documented in
+temporary activity markers remain for eating, rest, study, and patrol. The
+migration is documented in
 [the ResourceNode plan](RESOURCE_NODE_MIGRATION.md).
 
 ## Current technology
@@ -214,7 +215,8 @@ plugin content, not game architecture.
   follow/focus behavior.
 - Pressing `E` near a berry bush or tree extracts its configured yield into the
   village through the same `ResourceNode` contract used by NPCs.
-- Guard, study, and food interactions still use their temporary task zones.
+- Guard, study, rest, and food interactions still use temporary activity
+  markers.
 - `Escape` releases captured mouse input.
 
 ### Village simulation
@@ -288,24 +290,20 @@ result only when the task duration completes.
 Starvation can reduce productivity and eventually kill an NPC. Dead visuals
 stop moving, change appearance, and no longer collide.
 
-### Current task zones
+### Current activity markers
 
-The main scene contains placeholder zones for:
+The main scene contains placeholder activity markers for guard duty, study,
+rest, and food. The former farm and forest zones and their decorative geometry
+have been deleted.
 
-- farm;
+**Migration status:** NPC `gather_food` and `gather_wood` target `ResourceNode`
-- forest;
+instances (berry bushes and trees), with no marker fallback. The remaining
-- guard duty;
+markers are direct transitional targets for non-resource NPC tasks:
-- study;
-- rest;
-- food.
 
-The farm, forest, guard, study, rest, and food locations are represented by
+- patrol → guard marker;
-primitive geometry and a few tree assets.
+- study → study marker;
-
+- rest → rest marker;
-**Migration status:** NPC `gather_food` and `gather_wood` no longer use the
+- eat → food marker.
-farm and forest zones. They target `ResourceNode` instances (berry bushes and
-trees) instead. The zone markers remain for:
-- Non-resource NPC tasks (patrol → guard_zone, study → study_zone, rest → rest_zone, eat → food_zone)
 
 The player also harvests food and wood directly from nearby `ResourceNode`
 instances. Extraction returns the actual amount removed, updates the village by
@@ -465,8 +463,10 @@ NpcVisual navigates through the active world
 ├── simulation/
 │   ├── SimNPC.gd
 │   ├── SimVillage.gd
+│   ├── SimulationClock.gd
 │   └── SimulationManager.gd
 ├── tests/
+│   ├── deterministic_simulation_test.gd
 │   ├── flat_map_baseline_test.gd
 │   ├── jajce_world_scaffold_test.gd
 │   └── resource_node_player_parity_test.gd
@@ -493,14 +493,17 @@ NpcVisual navigates through the active world
 
 These are expected prototype constraints, not necessarily isolated bugs:
 
-- Task names and task-to-zone mappings are duplicated strings.
+- Task names and task-to-activity-marker mappings are duplicated strings.
-- Task zones remain for non-resource activities; NPC and player food/wood
+- Temporary activity markers remain for eating, rest, study, and patrol; NPC
-  gathering use `ResourceNode` instances.
+  and player food/wood gathering use `ResourceNode` instances with no fallback.
 - Mutable simulation state is not serializable through a defined save schema.
-- Randomness is not seeded for deterministic replay.
+- Simulation randomness is seeded and split into controlled per-NPC streams,
-- Simulation time depends on `_process` and a scene-tree node.
+  but RNG state is not yet part of a serializable save record.
-- Automated coverage currently contains one headless player-parity and
+- An explicit fixed-step clock converts frame delta into simulation ticks, but
-  resource-contention scenario; broader simulation coverage is still missing.
+  orchestration still lives on the scene-tree `SimulationManager`.
+- Automated coverage includes deterministic same-seed checksum,
+  player-parity/resource-contention, flat-map, and Jajce scaffold scenarios;
+  broader gameplay coverage is still missing.
 - Resources are global floating-point counters rather than items in locations
   and inventories.
 - NPCs do not have homes, schedules, possessions, memories, relationships,
@@ -710,10 +713,14 @@ Food and wood migration and the deliberately minimal `JajceWorld` scaffold,
 greybox, navigation spike, and stable-ID placement proof are complete. Do not
 proceed directly from that proof into open-ended beauty production.
 
-The architecture gate is now the active milestone:
+The architecture gate is now the active milestone. Its first slice is complete:
+
+- explicit fixed-step simulation clock;
+- seeded per-NPC decision and wander random streams;
+- headless fixed-seed scenario with a final-state checksum.
+
+The remaining gate work is:
 
-- 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;

docs/RESOURCE_NODE_MIGRATION.md

@@ -10,11 +10,11 @@
 | **4a** | Wood target selection (NPC) | ✅ Complete |
 | **4b** | Player parity (extraction contract) | ✅ Complete |
 | **5** | Jajce world placement | 🔶 Scaffold/navigation proof complete |
-| **6** | Remove remaining zone model | ❌ Not started |
+| **6** | Replace remaining activity markers | 🔶 Resource zones removed; activity targets pending |
 
 ### Key divergences from the original plan
 
-- **Zone fallback removed** (Phase 3): `gather_food`/`gather_wood` no longer fall back to `FarmZone`/`ForestZone` markers when no resource node is available. The original plan called for a logged fallback; instead, the NPC goes idle (via `navigation_failed` → wander) to guarantee resource conservation. Player harvesting also uses resource nodes; remaining zones serve only non-resource activities.
+- **Zone fallback removed** (Phase 3): `gather_food`/`gather_wood` no longer fall back to `FarmZone`/`ForestZone` markers when no resource node is available. The original plan called for a logged fallback; instead, the NPC goes idle (via `navigation_failed` → wander) to guarantee resource conservation. The obsolete farm and forest scene nodes have now also been deleted. The remaining markers are temporary targets for eating, rest, study, and patrol—not resource fallbacks.
 - **`navigation_failed` signal** (discovered during Phase 4): Added a separate signal pathway to distinguish genuine arrival from navigation failure. The original plan treated all "arrivals" uniformly.
 - **Stale-path prevention** (discovered during Phase 4): Added `path_request_id` + `path_pending` to reject async path results that arrive after a new target was set or the NPC died.
 - **Duplicate node_id detection** (discovered during Phase 4): Added startup validation that disables nodes with duplicate IDs and pushes an error.
@@ -58,8 +58,9 @@ environment is integrated. It is easier to debug target selection, reservation,
 depletion, and task completion without terrain and navigation changes happening
 at the same time.
 
-The old zones remain only as a temporary fallback while actions are migrated.
+The old resource zones have been removed. Temporary activity markers remain
-They are not part of the target architecture.
+only for actions whose real target type does not exist yet. They are not
+fallbacks and are not part of the target architecture.
 
 ## Why this is the next systems step
 
@@ -172,7 +173,7 @@ Main
 │   ├── BerryBush_02
 │   ├── Tree_01
 │   └── Tree_02
-└── TaskZone              temporary fallback
+└── ActivityMarkers       temporary eat/rest/study/patrol targets
 ```
 
 When `JajceWorld` is integrated, move or recreate the world-object instances
@@ -493,7 +494,7 @@ deferred until after the architecture gate, so this phase is not yet complete.
 **Exit:** the existing food and wood loops work after moving from the flat map
 to Terrain3D.
 
-### Phase 6 — Remove the remaining zone model
+### Phase 6 — Replace the remaining activity-marker model
 
 This is not part of the first ResourceNode implementation.
 
@@ -513,7 +514,14 @@ Remove each old zone only when its replacement has:
 - debug visibility;
 - save representation.
 
-**Exit:** `TaskZone` and task-to-marker mapping are deleted, not merely unused.
+**Progress:** the `TaskZone` container and obsolete `FarmZone`/`ForestZone`
+nodes have been deleted from `main.tscn`. The surviving nodes live under
+`ActivityMarkers` to make their transitional role explicit. Task-to-marker
+mapping still exists for eating, rest, study, and patrol, so this phase is not
+complete.
+
+**Exit:** temporary activity markers and task-to-marker mapping are deleted,
+not merely unused.
 
 ## Test scenarios