geometry.face.absorb: tiny and sliver faces into a neighbour (#506)

A face merge may keep one of its faces' names (Merge::into, model
FaceMerge::into): absorbing a tiny face leaves the neighbour by its own
name, so sets on it still select it. Shape::absorbing_neighbour finds
the face a tiny one shares the longest edges with. geometry.face.absorb
absorbs one face (into a named or the best neighbour) or, from_check,
every small and sliver face the last geometry.check marked; check marks
now carry the small face they found.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

crates/engine/src/catalogue.rs

@@ -302,6 +302,13 @@ pub static CATALOGUE: &[Capability] = &[
         "Mesh adjacent faces as one (virtual topology): a fillet in pieces, a face split by an imprint; the B-rep is unchanged",
         &["geometry.faces.merge.delete"],
     ),
+    ready(
+        "geometry.face.absorb",
+        "Absorb Faces",
+        Geometry,
+        "Prepare",
+        "Absorb tiny and sliver faces into a neighbour for meshing, one picked or every one Check Geometry found",
+    ),
     soon("geometry.midsurface", "Midsurface", Geometry, "Prepare", "M8", "Extract midsurfaces of thin parts for shell meshes"),
     // ---- Mesh ----
     soon("mesh.size.global", "Global Size", Mesh, "Size", "M2", "One element size for the whole part"),