adding more nodes

docs/nodes/Affine Correction.md

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+# Affine Correction
+
+Fix geometric distortions from scanner nonlinearity by applying an affine transformation. Corrects shear, anisotropic scaling, and rotation. Equivalent to Gwyddion's correct_affine.c module.
+
+## Inputs
+
+| Name | Type | Required | Description |
+|------|------|----------|-------------|
+| field | DATA_FIELD | Yes | Input field with geometric distortion |
+
+## Outputs
+
+| Name | Type | Description |
+|------|------|-------------|
+| corrected | DATA_FIELD | Affine-corrected field |
+
+## Controls
+
+| Name | Type | Default | Description |
+|------|------|---------|-------------|
+| shear_x | FLOAT | 0.0 | Horizontal shear factor |
+| shear_y | FLOAT | 0.0 | Vertical shear factor |
+| scale_x | FLOAT | 1.0 | Horizontal scale factor |
+| scale_y | FLOAT | 1.0 | Vertical scale factor |
+| angle | FLOAT | 0.0 | Rotation angle in degrees |
+
+## Notes
+
+- An identity transform (shear=0, scale=1, angle=0) returns the original data unchanged.
+- The output shape matches the input; pixels outside the transformed region are filled by nearest-edge interpolation.
+- For simple rotation without scaling/shear, use the Rotate node instead.