Implement arrangement framework for node groups

- Introduced `frames.py` to manage field complex calculations and their arrangement within node groups.
- Added functionality to create and remove field frames based on node arrangements.
- Developed `passages.py` to find unobstructed paths for connections around calculation frames.
- Implemented `references.py` to route shared results on peripheral tracks, ensuring efficient distribution of outputs.
- Created `sections.py` to reserve space for field calculations adjacent to geometry consumers.
- Added `sources.py` to position shared calculation sources effectively beside their distribution channels.
- Enhanced outline smoothing with `outline_smoothing.py` to adapt camera depth along original outlines.

openspec/changes/compact-repeat-node-arrangement/design.md

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+## Context
+
+排列器以几何主链、取值支线及共享引用组织节点。循环目前额外计算支线宽度并预留两端间距。
+
+## Goals / Non-Goals
+
+目标是让循环执行步骤紧凑可读，并保持前置几何处理的横向先后关系。
+
+## Decisions
+
+- 预览层从完整区域成员中筛选几何执行主链，取值计算复用支线排列流程。
+- 横向列依赖保留实际几何来源，局部引用端口保持连接顺序。
+- 使用真实 Depth Cutout 和小型循环验证布局、连接及几何求值。
+- 简单计算链在有限高度内纵向分段，复杂支线按消费者形成独立 Frame。
+- 支线按实际消费输入与连通依赖分组，计算流程保持连续展开。
+- 几何引用线同时处理向前与回向连接，水平通道统一避让节点、支线及已有通道。
+- 引用线的高差通过有横向展开的斜向曲线过渡。
+
+## Risks / Trade-offs
+
+支线引用循环数据时可能需要回向连线；通过分离主链通道和支线区域保证可读性，并验证几何连接语义保持一致。