engine: mesh.size.* commands, honoured by every mesher (#435)

mesh.size.set adds a size control on faces, bodies, a box or a sphere;
mesh.size.growth sets the growth rate; mesh.size.clear and
mesh.size.list. The tet mesher bakes the controls into its graded field,
the hex meshers, cells and the octree take the graded RegionSize, and
the block projection and mesh plans divide their edges by it.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_01UhhZMBTviDQxZvwnyP89fo

docs/features.md

@@ -6,7 +6,7 @@ Every entry is a toolbar button. **Ready** entries run their command; **coming s
 shown greyed with the roadmap milestone that brings them (ROADMAP.md). Scripts, the command line,
 the control channel and AI agents over MCP (docs/mcp.md) run the same commands.
 
-82 ready, 37 coming soon.
+83 ready, 37 coming soon.
 
 ## Geometry
 
@@ -34,6 +34,7 @@ the control channel and AI agents over MCP (docs/mcp.md) run the same commands.
 |---|---|---|---|
 | Size | Global Size — One element size for the whole part | coming soon (M2) |  |
 | Size | Seed Edges — Element counts or sizes per design edge, with bias and an exact, minimum or free constraint; the meshers honour them | ready | `mesh.seed.edge`, `mesh.seed.clear`, `mesh.seed.list` |
+| Size | Local Size — Element size on faces or bodies, in a box or in a sphere, growing away at a set rate; every mesher honours it | ready | `mesh.size.set`, `mesh.size.growth`, `mesh.size.clear`, `mesh.size.list` |
 | Size | Curvature — Refine by curvature and proximity | coming soon (M2) |  |
 | Tet | Tet Mesh — Quality tet4 or tet10 mesh of a body to a size: refined, smoothed and improved, boundary on the B-rep faces, faces tagged | ready | `mesh.tet.generate` |
 | Tet | Quadratic — Second-order elements with mid-side nodes on the geometry | coming soon (M2) |  |