ocs_doc_api: fix review findings (layouts, Helix bounds, points_aabb, mass-properties budget, docs)

- layouts.json: append the 6 missing ops (CreateDimensionRadius/Diameter/Angular,
  CreateAttributeDefinition, CreateTable, CreateDimensionAngular2Ln); regenerate
  binding_schema.json + api_reference.md wire vocabulary (all 28 ops).
- Helix bounds: bound the evaluated spline control polygon (was a degenerate
  single-start-point AABB).
- points_aabb: empty -> Geometry::Empty('entity has no points to bound'), not
  UnknownId (the entity exists; don't misclassify as stale/deleted).
- mass_properties: accuracy-first fine tessellation + graceful degradation to the
  approximate meshes.metrics value when the cold-tess budget is exhausted (large
  distinct-solid batches no longer hard-fail).
- IMPLEMENTATION.md: Volume/Centroid rows + accuracy paragraph + test count (618)
  consistent with the final design.
- 618 host lib + 8 crate + 3 consistency green.

crates/ocs_doc_api/src/gen/api_reference.md

@@ -278,6 +278,12 @@ Every `Operation` is ONE atomic write op (one undo step); every `Query` is read-
 - `SetViewportView { id: ObjectId, view_target: [f64; 3], view_height: f64 }`
 - `CreateRasterImage(RasterImageSpec)`
 - `Loft { profiles: Vec<ObjectId> }`
+- `CreateDimensionRadius(DimensionRadialSpec)`
+- `CreateDimensionDiameter(DimensionRadialSpec)`
+- `CreateDimensionAngular(DimensionAngularSpec)`
+- `CreateAttributeDefinition(AttributeDefinitionSpec)`
+- `CreateTable(TableSpec)`
+- `CreateDimensionAngular2Ln(DimensionAngularSpec)`
 
 ### `Query`