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/improve-relief-depth-controls/tasks.md

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+## 1. Relief depth behavior
+
+- [x] 1.1 Add the public `Depth Offset` distance input to `O Image Relief Plane`, with a default of one and signed range; expose `Depth Direction`, `Depth Offset`, and `Depth Scale` directly below `Thickness` in that order.
+- [x] 1.2 Add `Depth Offset` to `Reference Depth` before `reference_plane_depth()`, then replace the thickness-dependent inward limit with a zero clamp after direction adjustment and `Depth Scale`, preserving fixed-base and side-layer weighting.
+
+## 2. Behavior verification
+
+- [x] 2.1 Update Relief Plane geometry tests to verify far depths stop at `Thickness`, positive depths remain unrestricted, and the fixed base and side interpolation remain valid.
+- [x] 2.2 Add positive, negative, and zero `Depth Offset` tests, including direction adjustment, `Depth Scale = 0`, and checks that Depth Offset is scaled as part of the corrected relative depth while the depth-zero height remains fixed.
+- [x] 2.3 Update the node-group interface inventory test for `Depth Direction` and `Depth Offset` names, order, panel placement, and old base-plane clamp behavior.
+
+## 3. Node asset
+
+- [x] 3.1 Run `uv run node-group build` to rebuild and validate `src/anyimage/assets/O_AnyImage.blend` from the updated source and tests.
+- [x] 3.2 Run the relevant Relief Plane and plane-object tests, then inspect the final diff for stale inward-limit nodes or old behavior references.
+
+## 4. Initial depth direction
+
+- [x] 4.1 Extract the robust plane-direction fit into `common.depth` and reuse it from Cutout Symmetry calibration.
+- [x] 4.2 Fit the complete valid Relief depth image in local plane coordinates and initialize the new Modifier's `Depth Direction`.
+- [x] 4.3 Add sloped-depth initialization and shared calibration regression tests.