feat: add nearby social interactions

_Core/ui/InteractionPointMarkers.gd

@@ -0,0 +1,20 @@
+extends Node2D
+
+# 地图内可交互目标的轻量视觉标记，由 InteractionManager 提供世界坐标。
+const RING_COLOR: Color = Color(1.0, 1.0, 1.0, 0.94)
+const CORE_COLOR: Color = Color(1.0, 1.0, 1.0, 0.58)
+const RING_RADIUS: float = 9.0
+const RING_WIDTH: float = 2.0
+
+var _points: Array[Vector2] = []
+
+func set_points(points: Array[Vector2]) -> void:
+	if _points == points:
+		return
+	_points = points.duplicate()
+	queue_redraw()
+
+func _draw() -> void:
+	for point: Vector2 in _points:
+		draw_arc(point, RING_RADIUS, 0.0, TAU, 24, RING_COLOR, RING_WIDTH, true)
+		draw_circle(point, 2.0, CORE_COLOR)