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/ops_gen.rs

@@ -7,7 +7,7 @@
 use serde::{Deserialize, Serialize};
 
 use crate::id::ObjectId;
-use crate::ops::{BoolOp, Curve2Spec, EntitySpec, InsertSpec, MTextSpec, PlacementSpec, SolidPrimitive, TextSpec, ViewportSpec};
+use crate::ops::{BoolOp, Curve2Spec, EntitySpec, HatchSpec, InsertSpec, MTextSpec, PlacementSpec, SolidPrimitive, TextSpec, ViewportSpec};
 
 /// A typed write operation (plan §5). Each variant is ONE atomic host call = one
 /// undo step. Append new variants at the END only.
@@ -36,4 +36,6 @@ pub enum Operation {
     CreateText(TextSpec),
     CreateMText(MTextSpec),
     SetTextContent { id: ObjectId, value: String },
+    // hatch
+    CreateHatch(HatchSpec),
 }