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/proposal.md

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+## Why
+
+Repeat 为取值支线预留宽度，导致单个 Set Position 的循环被拉长，前置循环的处理顺序也难以辨认。
+
+## What Changes
+
+- 按循环执行主链排列 Repeat 两端，取值支线独立排列。
+- 几何处理节点按真实上游依赖确定先后位置。
+- 更新排列测试、节点资产和交互预览。
+- 将长计算链紧凑排列，为复杂支线添加 Frame，并分离几何引用线通道。
+
+## Capabilities
+
+### New Capabilities
+
+- `compact-repeat-arrangement`: 紧凑呈现循环执行主链并保持几何处理顺序。
+
+### Modified Capabilities
+
+## Impact
+
+涉及 `tools/nodes/arrangement`、`tools/nodes/preview`、相关测试和 `O_AnyImage.blend`。