ocs_doc_api: Phase 3 attributes + nested block traversal

- SetAttribute op + GetAttributes/GetBlockEntities queries (append-only).
- backend set_attribute (add/update Insert attribute), attributes (tag,value pairs),
  block_entities (read-only traversal via BlockRecord.entity_handles -> id+kind+bounds).
- facade Entity::set_attribute/attributes, Document::block_entities.
- spec Insert methods; api_reference + binding_schema regenerated; mocks + baseline.
- Query enum: drop Copy (GetBlockEntities carries String).
- Test phase3_attributes_and_block_traversal -> 608 host lib + 3 consistency green.

crates/ocs_doc_api/src/gen/api_reference.md

@@ -145,6 +145,11 @@ Block reference. Place an existing BlockRecord by name; transform moves its inse
 
 - **create_insert**(`block_name: &str, insert_point: [f64; 3], scale: f64, rotation: f64`) -> `Entity`
 
+### Methods
+
+- **attributes**(``) -> `Vec<(String, String)>` — query `GetAttributes`
+- **set_attribute**(`tag: &str, value: &str`) -> `()` — op `SetAttribute`
+
 ## `Entity` (acadrust `Viewport`, collection `entities`)
 
 Paper-space viewport: a width×height window at center looking at view_target with view_height zoom. bounds = center ± w/2,h/2; transform moves center.

crates/ocs_doc_api/src/gen/binding_schema.json

@@ -300,7 +300,39 @@
       "acadrust_variant": "Insert",
       "collection": "entities",
       "handle": "Entity",
-      "methods": [],
+      "methods": [
+        {
+          "args": [],
+          "bulk": false,
+          "fixed": null,
+          "kind": "query",
+          "name": "attributes",
+          "op": null,
+          "query": "GetAttributes",
+          "read_only": true,
+          "returns": "Vec<(String, String)>"
+        },
+        {
+          "args": [
+            {
+              "name": "tag",
+              "ty": "&str"
+            },
+            {
+              "name": "value",
+              "ty": "&str"
+            }
+          ],
+          "bulk": false,
+          "fixed": null,
+          "kind": "op",
+          "name": "set_attribute",
+          "op": "SetAttribute",
+          "query": null,
+          "read_only": false,
+          "returns": "()"
+        }
+      ],
       "name": "Insert"
     },
     {

crates/ocs_doc_api/src/gen/ops_gen.rs

@@ -40,4 +40,6 @@ pub enum Operation {
     CreateHatch(HatchSpec),
     // dimensions
     CreateDimensionLinear(DimensionSpec),
+    // attributes
+    SetAttribute { id: ObjectId, tag: String, value: String },
 }

crates/ocs_doc_api/src/gen/query_gen.rs

@@ -9,7 +9,8 @@ use crate::id::ObjectId;
 
 /// A typed read query (plan §5). Read-only: no mutation, no undo, no revision
 /// bump. Safe to batch (`EnvelopeBody::Queries`). Append new variants at the END only.
-#[derive(Debug, Clone, Copy, PartialEq, Serialize, Deserialize)]
+/// (Not `Copy`: some variants carry owned data like a block name.)
+#[derive(Debug, Clone, PartialEq, Serialize, Deserialize)]
 #[non_exhaustive]
 pub enum Query {
     GetEntity { id: ObjectId },
@@ -25,4 +26,8 @@ pub enum Query {
     GetHatchBoundary { id: ObjectId },
     /// The measured value of a Dimension (distance or angle).
     GetDimensionMeasurement { id: ObjectId },
+    /// An insert's attributes as (tag, value) pairs.
+    GetAttributes { id: ObjectId },
+    /// The entity ids + kinds inside a block definition (read-only traversal).
+    GetBlockEntities { block_name: String },
 }