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/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.
-They are not part of the target architecture.
+The old resource zones have been removed. Temporary activity markers remain
+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