feat: runtime familiarity from shared work and utility exposure

NPCs who target the same resource or site concurrently gain mutual familiarity +0.1 per encounter, capped at 1.0. Action selection now receives the full NPC array and adds a +0.3 utility bonus for actions that familiar NPCs are currently performing - NPCs gravitate toward their housemates' professions. Inspector shows the highest-familiarity NPC with a percentage score under the resource lines.

world/ui/ui.gd

@@ -132,12 +132,14 @@ func _refresh_npc_inspector() -> void:
 		if not score_rows.is_empty():
 			score_text = "\n\nUtility\n" + "\n".join(score_rows)
 	var event_text := _build_event_history(npc)
+	var housemate_text := _build_housemate_display(npc)
 	npc_inspector_label.text = (
 		"%s  ·  %s\n"
 		+ "Task: %s (%s)\n"
 		+ "Destination: %s\n"
 		+ "Hunger: %.0f   Energy: %.0f\n"
-		+ "Carrying food: %.0f  wood: %.0f\n\n"
+		+ "Carrying food: %.0f  wood: %.0f\n"
+		+ "%s\n"
 		+ "Why\n%s%s\n\n"
 		+ "Recent\n%s\n\n"
 		+ "[Tab] Next villager   [F10] Cinematic/debug   [F12] Demo reset"
@@ -151,6 +153,7 @@ func _refresh_npc_inspector() -> void:
 		npc.energy,
 		npc.get_inventory_amount(SimulationIds.RESOURCE_FOOD),
 		npc.get_inventory_amount(SimulationIds.RESOURCE_WOOD),
+		housemate_text,
 		reason_text,
 		score_text,
 		event_text
@@ -188,3 +191,24 @@ func _build_event_history(npc: SimNPC) -> String:
 	for event in events:
 		lines.append(event.description(name_map))
 	return "\n".join(lines)
+
+
+func _build_housemate_display(npc: SimNPC) -> String:
+	if npc.familiarity.is_empty():
+		return ""
+	var highest_id: int = -1
+	var highest_score := -1.0
+	for key in npc.familiarity:
+		var other_id: int = int(key)
+		var score: float = float(npc.familiarity[key])
+		if score > highest_score:
+			highest_score = score
+			highest_id = other_id
+	if highest_id < 0:
+		return ""
+	var other_name := "Someone"
+	for other_npc in simulation_manager.npcs:
+		if other_npc.id == highest_id:
+			other_name = other_npc.npc_name
+			break
+	return "Familiar: %s (%.0f%%)" % [other_name, highest_score * 100.0]