Update README feature matrix with new terrain modules

Add Worley noise and hydraulic erosion rows. Update Terrain Generation
description to mention ridged noise, domain warping, Worley blending,
and erosion options.

Author: brendancol

README.md

@@ -243,12 +243,14 @@ In the GIS world, rasters are used for representing continuous phenomena (e.g. e
 | [Hillshade](xrspatial/hillshade.py) | Simulates terrain illumination from a given sun angle and azimuth | ✅️ | ✅️ | ✅️ | ✅️ |
 | [Roughness](xrspatial/terrain_metrics.py) | Computes local relief as max minus min elevation in a 3×3 window | ✅️ | ✅️ | ✅️ | ✅️ |
 | [Slope](xrspatial/slope.py) | Computes terrain gradient steepness at each cell in degrees | ✅️  | ✅️  | ✅️ | ✅️  |
-| [Terrain Generation](xrspatial/terrain.py) | Generates synthetic terrain elevation using fractal noise | ✅️ | ✅️ | ✅️ | ✅️ |
+| [Terrain Generation](xrspatial/terrain.py) | Generates synthetic terrain from fBm or ridged fractal noise with optional domain warping, Worley blending, and hydraulic erosion | ✅️ | ✅️ | ✅️ | ✅️ |
 | [TPI](xrspatial/terrain_metrics.py) | Computes Topographic Position Index (center minus mean of neighbors) | ✅️ | ✅️ | ✅️ | ✅️ |
 | [TRI](xrspatial/terrain_metrics.py) | Computes Terrain Ruggedness Index (local elevation variation) | ✅️ | ✅️ | ✅️ | ✅️ |
 | [Viewshed](xrspatial/viewshed.py) | Determines visible cells from a given observer point on terrain | ✅️ | ✅️ | ✅️ | ✅️ |
 | [Min Observable Height](xrspatial/experimental/min_observable_height.py) | Finds the minimum observer height needed to see each cell *(experimental)* | ✅️ | | | |
 | [Perlin Noise](xrspatial/perlin.py) | Generates smooth continuous random noise for procedural textures | ✅️ | ✅️ | ✅️ | ✅️ |
+| [Worley Noise](xrspatial/worley.py) | Generates cellular (Voronoi) noise returning distance to the nearest feature point | ✅️ | ✅️ | ✅️ | ✅️ |
+| [Hydraulic Erosion](xrspatial/erosion.py) | Simulates particle-based water erosion to carve valleys and deposit sediment | ✅️ | 🔄 | 🔄 | 🔄 |
 | [Bump Mapping](xrspatial/bump.py) | Adds randomized bump features to simulate natural terrain variation | ✅️ | ✅️ | ✅️ | ✅️ |
 
 -----------