feat: seed household familiarity from shared home proximity

NPCs whose home positions are within 4m of each other gain mutual familiarity at baseline 0.5. Stored per NPC as a Dictionary keyed by other npc_id, serialized through NPCStateRecord with backward-compatible fallback for old saves. Household pairs form naturally from the home_positions configuration in main.tscn. Includes save/load round-trip test verifying familiarity persists.

simulation/SimNPC.gd

@@ -32,6 +32,7 @@ var has_travel_target := false
 var inventory: Dictionary = {}
 var last_task: StringName
 var random_source: RandomNumberGenerator
+var familiarity: Dictionary = {}
 var debug_logs := true
 
 

simulation/SimulationManager.gd

@@ -86,6 +86,12 @@ func generate_npcs() -> void:
 		for i in range(npcs.size()):
 			npcs[i].home_position = home_positions[i % home_count]
 
+	for i in range(npcs.size()):
+		for j in range(i + 1, npcs.size()):
+			if npcs[i].home_position.distance_to(npcs[j].home_position) < 4.0:
+				npcs[i].familiarity[npcs[j].id] = 0.5
+				npcs[j].familiarity[npcs[i].id] = 0.5
+
 
 func _create_random_source(npc_id: int, stream_id: int) -> RandomNumberGenerator:
 	var source := RandomNumberGenerator.new()

simulation/state/NPCStateRecord.gd

@@ -45,7 +45,8 @@ static func capture(npc: SimNPC) -> NPCStateRecord:
 			"inventory": npc.inventory.duplicate(true),
 			"last_task": String(npc.last_task),
 			"random_seed": str(npc.random_source.seed),
-			"random_state": str(npc.random_source.state)
+			"random_state": str(npc.random_source.state),
+			"familiarity": npc.familiarity.duplicate(true)
 		}
 	)
 
@@ -160,6 +161,9 @@ func restore(debug_logs: bool) -> SimNPC:
 	npc.last_task = StringName(data["last_task"])
 	npc.random_source.state = String(data["random_state"]).to_int()
 	npc.debug_logs = debug_logs
+	var saved_familiarity = data.get("familiarity", {})
+	if saved_familiarity is Dictionary:
+		npc.familiarity = saved_familiarity.duplicate(true)
 	return npc