ocs_doc_api: Phase 2b-c (linear Dimension) — Phase 2 complete

- CreateDimensionLinear(DimensionSpec) op + GetDimensionMeasurement query (append-only).
- backend add_dimension_linear (Dimension::Linear via DimensionLinear::new) +
  dimension_measurement (linear/radius/diameter distance).
- Dimension bounds from measured + definition points; Dimension handle + measurement().
- spec Dimension family; api_reference + binding_schema regenerated; mocks + baseline.
- Test phase2c_dimension_linear_create_measurement_bounds -> 607 host lib + 8 crate
  + 3 consistency green. Phase 2 (full 2D + annotations) is now complete.

crates/ocs_doc_api/src/gen/api_reference.md

@@ -125,6 +125,18 @@ Filled region over a closed polyline boundary. boundary() returns the loops; bou
 
 - **boundary**(``) -> `Vec<Vec<[f64; 2]>>` — query `GetHatchBoundary`
 
+## `Dimension` (acadrust `Dimension`, collection `curves`)
+
+Linear dimension between two measured points. measurement() reads the distance; bounds from the measured + definition points.
+
+### Constructors (`doc.curves()`)
+
+- **create_dimension_linear**(`first_point: [f64; 3], second_point: [f64; 3], definition_point: [f64; 3]`) -> `Dimension`
+
+### Methods
+
+- **measurement**(``) -> `f64` — query `GetDimensionMeasurement`
+
 ## `Entity` (acadrust `Insert`, collection `entities`)
 
 Block reference. Place an existing BlockRecord by name; transform moves its insert point.

crates/ocs_doc_api/src/gen/binding_schema.json

@@ -277,6 +277,25 @@
       ],
       "name": "Hatch"
     },
+    {
+      "acadrust_variant": "Dimension",
+      "collection": "curves",
+      "handle": "Dimension",
+      "methods": [
+        {
+          "args": [],
+          "bulk": false,
+          "fixed": null,
+          "kind": "query",
+          "name": "measurement",
+          "op": null,
+          "query": "GetDimensionMeasurement",
+          "read_only": true,
+          "returns": "f64"
+        }
+      ],
+      "name": "Dimension"
+    },
     {
       "acadrust_variant": "Insert",
       "collection": "entities",
@@ -361,7 +380,8 @@
       "Ray",
       "XLine",
       "Text",
-      "MText"
+      "MText",
+      "Dimension"
     ],
     "root": "DocApi"
   },

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, HatchSpec, InsertSpec, MTextSpec, PlacementSpec, SolidPrimitive, TextSpec, ViewportSpec};
+use crate::ops::{BoolOp, Curve2Spec, DimensionSpec, 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.
@@ -38,4 +38,6 @@ pub enum Operation {
     SetTextContent { id: ObjectId, value: String },
     // hatch
     CreateHatch(HatchSpec),
+    // dimensions
+    CreateDimensionLinear(DimensionSpec),
 }

crates/ocs_doc_api/src/gen/query_gen.rs

@@ -23,4 +23,6 @@ pub enum Query {
     GetTextContent { id: ObjectId },
     /// The boundary loops of a Hatch (outer + islands) as polylines.
     GetHatchBoundary { id: ObjectId },
+    /// The measured value of a Dimension (distance or angle).
+    GetDimensionMeasurement { id: ObjectId },
 }