Refactor depth surface handling and unify depth sampling rules

- Removed the `always_vertex` parameter from `build_surface_camera` to streamline depth sampling for cutouts and ensure consistent behavior across depth plane and panorama.
- Updated depth sampling logic to ensure that all free boundary points, including the original frame of the depth plane, use neighboring face depth instead of their own texture sampling.
- Adjusted the depth mask deletion process to operate on faces rather than points, eliminating the need for additional cleanup of dangling edges.
- Ensured that the cutout rules are consistently applied across all relevant nodes, removing exceptions and simplifying the logic.
- Updated tests to verify the new behavior, ensuring that cutout points follow the depth of adjacent faces and that the original frame maintains its depth sampling.
- Refactored geometry handling in multiple depth-related nodes to improve clarity and maintainability.

openspec/changes/refine-cutout-symmetry-seam/tasks.md

@@ -9,15 +9,15 @@
 
 ## 2. 节点测试
 
-- [ ] 2.1 断言输出不存在越过对称面的顶点、整体贴平面的面或四面共边
-- [ ] 2.2 断言 Fill Sides 开启时网格封闭、边与顶点流形、镜像成立，并覆盖零厚度与非零厚度输入
-- [ ] 2.3 断言 Fill Sides 关闭时切口自焊，落在对称面上的边没有开边
+- [x] 2.1 断言输出不存在越过对称面的顶点、整体贴平面的面或四面共边
+- [x] 2.2 断言 Fill Sides 开启时网格封闭、边与顶点流形、镜像成立，并覆盖零厚度与非零厚度输入
+- [x] 2.3 断言 Fill Sides 关闭时切口自焊，落在对称面上的边没有开边
 - [ ] 2.4 断言 Seam Smooth 大于 0 时切口对称轴坐标不漂移，且按两圈渐变影响切口邻域
-- [ ] 2.5 断言节点组不含布尔节点，接口只新增 Seam Smooth
+- [x] 2.5 断言节点组不含布尔节点，接口只新增 Seam Smooth
 
 ## 3. 验证
 
 - [x] 3.1 运行 `uv run node-group build --skip-tests` 并确认资产重载校验通过
-- [ ] 3.2 更新节点测试后运行 `uv run pytest tests/tools/nodes/test_cutout_symmetry.py`
-- [ ] 3.3 运行受影响的 Cutout 对象创建测试
+- [x] 3.2 更新节点测试后运行 `pytest tests/tools/nodes/test_cutout_symmetry.py`，全部通过
+- [x] 3.3 运行受影响的 Cutout 对象创建测试
 - [x] 3.4 记录样例上折叠前越界量分布，作为折面跨度的验证证据