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.

src/app/plugin_host.rs

@@ -18,6 +18,10 @@ pub(crate) struct HostSession<'a> {
     doc_store: Option<DocumentSnapshotStore<DocumentViewData>>,
     /// In-flight DocApi v2 undo delta (between `push_undo` and `finalize_op`).
     doc_api_pending: Option<super::history::PendingDelta>,
+    /// Memoized volume/centroid per (handle, geometry_epoch) for DocApi mass queries.
+    pub(crate) mass_cache: std::collections::HashMap<Handle, (u64, f64, [f64; 3])>,
+    /// Per-session count of cold-cache mass tessellations (budget for query DoS).
+    pub(crate) cold_tess_used: usize,
 }
 
 impl<'a> HostSession<'a> {
@@ -27,6 +31,8 @@ impl<'a> HostSession<'a> {
             tab,
             doc_store: None,
             doc_api_pending: None,
+            mass_cache: std::collections::HashMap::new(),
+            cold_tess_used: 0,
         }
     }