feat: Add new Geometry Nodes groups for image relief and shadeless shader

- Implemented the "O Image Relief Plane" Geometry Nodes group to create a fixed-base image relief using depth images and various parameters.
- Created the "O Shadeless" shader node group to display color without scene lighting while preserving shadows and reflections.
- Introduced a preview feature for node groups, allowing for interactive visualization of node arrangements in an HTML format.
- Added a template HTML file for rendering node previews with customizable views and controls.

src/anyimage/server/geometry/edge_depth.py

@@ -1,4 +1,4 @@
-"""Extend reliable Cutout depth along each visible component's silhouette."""
+"""Extend reliable depth along each visible component's silhouette."""
 
 from dataclasses import replace
 
@@ -18,19 +18,20 @@ def extend_edge_depth(frame, alpha, alpha_threshold=0.9):
         return frame
 
     visible = (alpha > 0.0) & (alpha >= alpha_threshold)
+    opaque = visible & (alpha >= 0.95)
     candidates = (
-        visible
-        & (alpha >= 0.95)
-        & (frame.validity > 0.0)
+        opaque
+        & (frame.validity > 0.5)
         & np.isfinite(depth)
         & (depth > 0.0)
     )
     if not candidates.any():
         return frame
     interior_distance = ndimage.distance_transform_edt(
-        np.pad(candidates, 3, mode="edge")
+        np.pad(opaque, 3, mode="edge")
     )[3:-3, 3:-3]
-    core = candidates & (interior_distance > 2.0)
+    interior = opaque & (interior_distance > 2.0)
+    core = candidates & interior
     del interior_distance
     labels, _ = ndimage.label(visible, structure=np.ones((3, 3), dtype=bool))
     corrected = depth.copy()
@@ -59,7 +60,7 @@ def extend_edge_depth(frame, alpha, alpha_threshold=0.9):
             & (distance <= 4.0)
             & (distance < background_distance[region])
         )
-        target = (component & ~donors) | background
+        target = (component & ~interior[region] & ~donors) | background
         corrected[region][target] = smoothed[target]
         background_distance[region][background] = distance[background]