docs: mark simulation state phase complete

docs/PROJECT_CONTEXT.md

@@ -464,12 +464,14 @@ NpcVisual navigates through the active world
 │   ├── SimNPC.gd
 │   ├── SimVillage.gd
 │   ├── SimulationClock.gd
-│   └── SimulationManager.gd
+│   ├── SimulationManager.gd
+│   └── state/                 Versioned simulation-state records
 ├── tests/
 │   ├── deterministic_simulation_test.gd
 │   ├── flat_map_baseline_test.gd
 │   ├── jajce_world_scaffold_test.gd
-│   └── resource_node_player_parity_test.gd
+│   ├── resource_node_player_parity_test.gd
+│   └── simulation_state_serialization_test.gd
 ├── terrain/jajce/             Dedicated Terrain3D seed data and assets
 ├── tools/
 │   └── generate_jajce_terrain_seed.gd
@@ -496,14 +498,15 @@ These are expected prototype constraints, not necessarily isolated bugs:
 - Task names and task-to-activity-marker mappings are duplicated strings.
 - Temporary activity markers remain for eating, rest, study, and patrol; NPC
   and player food/wood gathering use `ResourceNode` instances with no fallback.
-- Mutable simulation state is not serializable through a defined save schema.
-- Simulation randomness is seeded and split into controlled per-NPC streams,
-  but RNG state is not yet part of a serializable save record.
+- Current NPC, village, loaded resource, clock, and RNG state serialize through
+  schema v1, but there is no save-slot/file UX or backward migration yet.
+- Resource records currently mirror loaded ResourceNode state; the scene nodes
+  still own live amounts and reservations.
 - An explicit fixed-step clock converts frame delta into simulation ticks, but
   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.
+- Automated coverage includes deterministic same-seed and save/restore
+  continuation checks, 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,
@@ -713,15 +716,18 @@ 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. Its first slice is complete:
+The architecture gate is now the active milestone. Its first two slices are
+complete:
 
 - explicit fixed-step simulation clock;
 - seeded per-NPC decision and wander random streams;
-- headless fixed-seed scenario with a final-state checksum.
+- headless fixed-seed scenario with a final-state checksum;
+- versioned JSON records for NPC, village, loaded resource, clock, and RNG
+  state;
+- deterministic save/restore continuation with exact 64-bit RNG preservation.
 
 The remaining gate work is:
 
-- 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;