feat: node graph overlay; move to opencadcodec/opencadkernel/opencadgraph

The codec and kernel repositories and crates are renamed opencadcodec and
opencadkernel. Inside OCS they are depended on under short keys, so code
reads `codec::`, `kernel::` and the new `graph::` (opencadgraph, the node
graph engine). File-format and protocol spellings stay as they were: the
ACIS product id `acadrust`, the ACADRUST_* switches and the plugin
version keys `acadrust_version` / `acadrust_source`.

A button left of MCP on the command line opens a translucent node graph
over the viewport, with a palette of object, input, math, logic, list,
text and geometry nodes added by click or drag. An object node owns
drawing entities and its rows are the Properties panel's own rows for
them: the single-object page is extracted from refresh_properties as
entity_property_sections, values use the control protocol's
property_json, and writes go through set_property_value with a property
target override, so the panel, MCP and the graph share one read/write
path. A list reaching an object row makes one entity per element. Each
graph action is one undo step; the canvas pans and zooms.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

crates/ocs_plugin_api/src/host.rs

@@ -1,6 +1,6 @@
 //! Runtime host surface (`host` feature).
 //!
-//! [`HostApi`] is the `acadrust`-typed adapter a plugin uses at *dispatch* time
+//! [`HostApi`] is the `opencadcodec`-typed adapter a plugin uses at *dispatch* time
 //! — document access, entity creation, XDATA, undo, and the command line. It is
 //! the stable counterpart to the dependency-free manifest/ribbon contract: a
 //! plugin's `dispatch` receives `&mut dyn HostApi` rather than the host's
@@ -19,16 +19,16 @@ use serde::{Deserialize, Deserializer, Serialize, Serializer};
 use crate::manifest::PluginManifest;
 use crate::ribbon::CadModule;
 
-// Re-export the acadrust crate and the types that appear in the HostApi trait
-// so out-of-tree plugins can use them without adding their own acadrust
+// Re-export the opencadcodec crate and the types that appear in the HostApi trait
+// so out-of-tree plugins can use them without adding their own opencadcodec
 // dependency (which would risk an ABI-mismatching version).
-pub use acadrust;
-pub use acadrust::objects::{
+pub use codec;
+pub use codec::objects::{
     DictionaryCloningFlags, KnownXRecordKind, ProxyObjectReference, ProxyReferenceKind, XRecord,
     XRecordEntry, XRecordSection, XRecordValue, XRecordValueType,
 };
-pub use acadrust::xdata::{ExtendedDataRecord, XDataValue};
-pub use acadrust::{CadDocument, EntityType, Handle};
+pub use codec::xdata::{ExtendedDataRecord, XDataValue};
+pub use codec::{CadDocument, EntityType, Handle};
 
 use crate::ipc::protocol::{PluginRequest, PluginResponse};
 
@@ -1016,14 +1016,14 @@ pub trait HostApi {
 #[derive(Debug, Clone, PartialEq, Serialize, Deserialize, Default)]
 pub struct LayerConfig {
     pub name: String,
-    pub color: Option<acadrust::types::Color>,
+    pub color: Option<codec::types::Color>,
     pub linetype: Option<String>,
-    pub lineweight: Option<acadrust::types::LineWeight>,
+    pub lineweight: Option<codec::types::LineWeight>,
     pub off: Option<bool>,
     pub frozen: Option<bool>,
     pub locked: Option<bool>,
     pub plottable: Option<bool>,
-    pub transparency: Option<acadrust::types::Transparency>,
+    pub transparency: Option<codec::types::Transparency>,
     pub description: Option<String>,
 }