ocs_doc_api: fix review findings (scale/rotation/all-or-nothing/DoS/bounds/codegen)

CRITICAL:
- transform_entity_geometry: fix s^2 double-scale (axes already carry scale; drop
  the *s pre-multiply so 2D entities scale by s like solids), and handle rotation
  for direction/angle fields (apply_dir for Ray/XLine direction + Ellipse
  major_axis; offset Arc angles; compose Insert rotation).
- ensure_transformable: check layer-lock + resolve solid bodies (not just type),
  restoring TransformMany all-or-nothing; regression test with a locked layer.

WARNING:
- volume/centroid: memoize per (handle, geometry_epoch) + cap cold-cache
  tessellation budget (query-batch DoS).
- entity_to_profile_curves: fail Unsupported on polyline bulge (no silent
  chord-substituted sweep profile).
- Ellipse: validate minor_axis_ratio in (0,1] so bounds never under-bound.
- RasterImage bounds: bracket all four corners (rotated/flipped images).

SUGGESTION:
- binding_schema.json handles derived from spec families (includes ArcCurve/
  Ellipse/Spline/Ray/XLine).
- build.rs header: enums are hand-maintained (not 'GENERATED'); ops_gen/query_gen
  headers corrected to match.
- Dedupe divergence mesh_volume_centroid into the crate's geom module; host +
  both mocks delegate.

Tests: +3 regression tests (scale-once, rotation, locked-layer all-or-nothing)
-> 604 host lib green; 8 crate unit tests green.

crates/ocs_doc_api/examples/common/mod.rs

@@ -204,25 +204,8 @@ impl DocApiBackend for MockBackend {
     }
 }
 
-/// Signed volume + centroid of a closed mesh via the divergence theorem.
+/// Signed volume + centroid of a closed mesh — delegates to the crate's single
+/// source of truth (divergence theorem) so the example mock can't drift.
 fn mesh_vc(mesh: &cadkernel::brep::Mesh) -> (f64, [f64; 3]) {
-    let mut vol = 0.0;
-    let mut c = [0.0; 3];
-    for t in &mesh.triangles {
-        let (v0, v1, v2) = (mesh.positions[t[0]], mesh.positions[t[1]], mesh.positions[t[2]]);
-        let cross = [
-            v1[1] * v2[2] - v1[2] * v2[1],
-            v1[2] * v2[0] - v1[0] * v2[2],
-            v1[0] * v2[1] - v1[1] * v2[0],
-        ];
-        let tet = (v0[0] * cross[0] + v0[1] * cross[1] + v0[2] * cross[2]) / 6.0;
-        vol += tet;
-        for i in 0..3 {
-            c[i] += (v0[i] + v1[i] + v2[i]) * tet;
-        }
-    }
-    if vol.abs() < 1e-12 {
-        return (0.0, [0.0; 3]);
-    }
-    (vol, [c[0] / (4.0 * vol), c[1] / (4.0 * vol), c[2] / (4.0 * vol)])
+    ocs_doc_api::geom::mesh_volume_centroid(mesh)
 }