ocs_doc_api: Phase 2b-b (Hatch)

- CreateHatch(HatchSpec) op + GetHatchBoundary query (append-only).
- HatchSpec{boundary: Vec<[f64;2]>, solid}; executor validates >= 3 boundary points.
- backend add_hatch (Line-edge BoundaryPath, solid/pattern) + hatch_boundary
  (reconstruct loops from Line edges; non-line edges -> Unsupported).
- Hatch bounds from boundary edges; facade create_hatch + Entity handle.
- spec Hatch family; api_reference + binding_schema regenerated; mocks + baseline.
- Test phase2b_hatch_create_boundary_bounds_delete -> 606 host lib + 8 crate + 3 consistency green.

crates/ocs_doc_api/src/gen/query_gen.rs

@@ -21,4 +21,6 @@ pub enum Query {
     GetGeometryRevision,
     /// The text content of a Text/MText annotation.
     GetTextContent { id: ObjectId },
+    /// The boundary loops of a Hatch (outer + islands) as polylines.
+    GetHatchBoundary { id: ObjectId },
 }