Add specifications for two-times upscale and unified depth plane features

- Introduced the two-times upscale specification detailing requirements for unified output, fixed model presets, arbitrary dimensions, and consistent job behavior.
- Added scenarios for existing models, repeated upscale, and handling of alpha preservation.
- Created the unified depth plane specification outlining geometry modes, stable interface, and asset evaluation.
- Defined scenarios for mode switching, relief and camera preservation, and validation of delivered assets.

openspec/specs/cutout-boundary-smoothing/spec.md

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+# cutout-boundary-smoothing Specification
+
+## Purpose
+TBD - created by archiving change weight-cutout-boundary-smoothing. Update Purpose after archive.
+## Requirements
+### Requirement: Boundary-specific smoothing strength
+
+`O Image Depth Cutout` SHALL 使用单个 `Boundary Smooth` 输入控制边界平滑次数。Split 边 SHALL 使用完整 `Smooth Weight`，原始 Outline SHALL 使用 `0.1` 倍 `Smooth Weight`；两类影响相交时 Split 强度 MUST 优先。
+
+#### Scenario: Separate Split and Outline response
+
+- **WHEN** 同一网格同时存在 Split 边与原始 Outline 且启用 Boundary Smooth
+- **THEN** Split 边按完整 Smooth Weight 平滑
+- **AND** 仅受 Outline 影响的点按其 0.1 倍平滑
+
+#### Scenario: Split and Outline intersection
+
+- **WHEN** Split 与 Outline 的两圈影响范围相交
+- **THEN** 相交区域使用两者中较强的 Split influence
+
+### Requirement: Boundary Smooth default and bypass
+
+`O Image Depth Cutout` 的 `Boundary Smooth` SHALL 默认为 `4`，保持范围 `0–16`；值为 `0` 时 MUST 完全旁路边界平滑。
+
+#### Scenario: New node group defaults
+
+- **WHEN** 构建新的 O Image Depth Cutout 节点组
+- **THEN** Boundary Smooth 默认值为 4
+
+#### Scenario: Disabled boundary smoothing
+
+- **WHEN** Boundary Smooth 为 0
+- **THEN** Split 边和 Outline 均不发生边界平滑位移
+