ocs_doc_api: update docs + fix review-drift findings

- lib.rs: export all 14 facade handles (add ArcCurve/Ellipse/Spline/Ray/XLine/Text/
  MText/Dimension + Circle) — public surface matches collection return types.
- build.rs: fix step-1 comment (enums are hand-maintained, not 'regenerated');
  generic_reference_md: Clone (not Copy) + full 14-handle list (was stale 6).
- ops.rs/query.rs: correct 'hand-maintained' module doc comments (were 'GENERATED').
- layouts.json: extend to all 22 Operation + 12 Query variants (was stale phase-1).
- binding_schema.json regenerated (complete layouts + derived handles).
- generate.py: inject 'id': self.id for SetTextContent/SetAttribute/SetViewportView/
  Transform/Delete/AddVertex (was malformed id-less payloads); _apply_op/_apply_query
  accept want=None; extend PY_TYPES (String/&str/Vec returns/new handles).
- README.md: Clone (not Copy) + full scope (2D curves, annotations, containers,
  viewports, media) replacing stale 'Not yet' list.
- Plan (.kilo): mark implemented & published; pointer to live crate docs.

crates/ocs_doc_api/src/ops.rs

@@ -1,7 +1,8 @@
 //! Write operations — the typed, transport-agnostic vocabulary for changing the
-//! document (plan §5). The `Operation` enum itself is GENERATED into
-//! `crate::gen` by `build.rs` from `spec/entities.toml`; this module re-exports
-//! it and holds the hand-written payload mirrors.
+//! document (plan §5). The `Operation` enum is **hand-maintained** (append-only)
+//! in `src/gen/ops_gen.rs` — it is NOT derived from the spec by build.rs; the
+//! spec's `op` names must each map to a variant here (asserted by a test). This
+//! module re-exports it and holds the hand-written payload mirrors.
 
 use serde::{Deserialize, Serialize};