feat(cutout): implement boundary padding for cutout textures

- Introduced a new `Boundary Padding` preference in the Cutout Tool with a default of 2 px and a configurable range of 1-4 px.
- Updated the Cutout client to establish inward mapping from the final Mask, sampling in a fixed direction and processing independent material RGBA and Depth.
- Enhanced the handling of RGBA and Depth during cutout operations, ensuring proper mapping and preservation of source data.
- Added tests to validate the new boundary padding functionality and its integration with existing cutout processes.

feat(geometry): remove overall mesh smoothing from geometry nodes

- Removed the `Smooth` input from several geometry node groups to eliminate unnecessary overall mesh smoothing.
- Retained `Smooth Weight` for depth nodes while removing it from Cutout and Relief Plane nodes.
- Ensured that boundary, normal, and fill smoothing behaviors remain intact and consistent.
- Updated tests and documentation to reflect the changes in node interfaces and behaviors.

feat(normals): scale tangent normals with depth

- Reused the existing `o_normal_reduction` attribute to adjust Tangent Normal strength based on the geometry's `Depth Scale`.
- Ensured that Tangent Normal strength is consistent with the geometry depth, preserving full strength for materials that do not provide the attribute.
- Updated tests to verify the correct behavior of normal strength adjustments in both Tangent and Object Space.

openspec/changes/remove-geometry-node-smoothing/proposal.md

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+## Why
+
+几何节点组当前在主体几何构建完成后提供一轮可选的整体 mesh smooth，既增加节点接口与实现复杂度，也会软化已经确定的表面细节。应移除这类末端后处理，同时保留边界平滑、法线平滑等独立业务所需的控制与权重。
+
+## What Changes
+
+- **BREAKING**：从所有相关几何节点组公开接口移除 `Smooth` 输入，生成结果不再执行末端整体 mesh smooth。
+- 删除仅服务于末端整体 smooth 的节点链、构建调用与测试约束。
+- `Smooth Weight` 若仍被 `Boundary Smooth` 等独立处理使用则保留；若只控制已删除的末端 smooth，则连同接口与相关逻辑删除。
+- 保留 `Boundary Smooth`、`Normal Smooth`、shade smooth，以及深度/轮廓生成过程中的其他专用平滑行为。
+- 重建并验证 `O_AnyImage.blend`，同步节点组接口清单、布局预期及相关内部说明。
+
+## Capabilities
+
+### New Capabilities
+
+- `geometry-node-smoothing`: 规定几何节点输出不得追加整体 mesh smooth，并明确专用平滑控制及共享权重的保留规则。
+
+### Modified Capabilities
+
+无。
+
+## Impact
+
+- 影响 `O Image Cutout`、`O Image Depth Cutout`、`O Image Depth Plane`、`O Image Depth Panorama`、`O Image Relief Plane` 的公开 modifier 接口与生成图。
+- 影响 `tools/nodes/groups`、共享 smoothing 构建代码的实际引用、节点资产与节点相关测试。
+- 现有依赖 `Smooth` socket identifier 的 modifier 配置或调用方需要停止写入该输入；`Smooth Weight` 只在没有其他消费者的节点组中移除。