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/scale-tangent-normals-with-depth/specs/depth-scaled-tangent-normals/spec.md

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+## ADDED Requirements
+
+### Requirement: Normal strength follows geometry depth scale
+When a Geometry Nodes group both exposes `Depth Scale` and is rendered with a normal map, it SHALL store `1 - Depth Scale` as the `o_normal_reduction` float attribute on its final geometry. `O Image Layer` SHALL calculate Tangent and Object Normal Map Strength as its `Normal Scale` input multiplied by `1 - o_normal_reduction`.
+
+#### Scenario: Reduced relief depth reduces Tangent normal strength
+- **WHEN** an O Image Relief Plane uses a Tangent normal map and `Depth Scale` is set to 0.5
+- **THEN** the Tangent Normal Map Strength is one half of the value produced at `Depth Scale` 1 with the same `Normal Scale` input
+
+#### Scenario: Zero relief depth disables Tangent normal detail
+- **WHEN** an O Image Relief Plane uses a Tangent normal map and `Depth Scale` is set to 0
+- **THEN** the Tangent Normal Map Strength is zero
+
+#### Scenario: Depth extrapolation is preserved
+- **WHEN** an eligible Tangent-normal geometry group uses `Depth Scale` greater than 1
+- **THEN** `o_normal_reduction` is negative by the corresponding amount and the Tangent Normal Map Strength retains the extrapolated value without clamping
+
+### Requirement: Reduction attribute retains its material fallback
+`O Image Layer` SHALL use a factor of 1 for its Tangent Normal Map Strength when `o_normal_reduction` is absent. The existing `o_normal_reduction` material contract SHALL remain unchanged.
+
+#### Scenario: Ordinary image material has no normal-scale attribute
+- **WHEN** an object using O Image Layer has no `o_normal_reduction` attribute
+- **THEN** its Tangent Normal Map Strength equals the `Normal Scale` input
+
+#### Scenario: Object Space normal strength follows the reduction
+- **WHEN** O Image Layer is configured for an Object Space normal map and its geometry has any `o_normal_reduction` value
+- **THEN** the Object Space Normal Map Strength equals the `Normal Scale` input multiplied by `1 - o_normal_reduction`