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 <[email protected]>

src/entities/common.rs

@@ -34,7 +34,7 @@ impl UnitContext {
     /// The settings as this drawing holds them. Every place that formats or
     /// reads a number seeds the context from here, so none of them can be
     /// working from a different idea of the drawing's conventions.
-    pub fn from_header(header: &acadrust::document::HeaderVariables) -> Self {
+    pub fn from_header(header: &codec::document::HeaderVariables) -> Self {
         Self {
             lunits: header.linear_unit_format,
             luprec: header.linear_unit_precision,
@@ -71,7 +71,7 @@ thread_local! {
 }
 
 /// Record which text styles fix their height, from the drawing's style table.
-pub fn set_fixed_text_heights(document: &acadrust::CadDocument) {
+pub fn set_fixed_text_heights(document: &codec::CadDocument) {
     FIXED_TEXT_HEIGHTS.with(|cell| {
         let mut map = cell.borrow_mut();
         map.clear();
@@ -754,7 +754,7 @@ fn parse_angle_deg_unbounded(value: &str) -> Option<f64> {
 /// Re-exported rather than imported at each call site so the twelve modules
 /// that already reach for `entities::common::BulgeArc` keep working, and so
 /// there is one obvious place to see that the maths moved out.
-pub use cadkernel::geom2d::BulgeArc;
+pub use kernel::geom2d::BulgeArc;
 
 /// Convert a 2D BulgeArc into a 3D TangentGeom::Arc with its world center,
 /// plane axes, radius, and counter-clockwise start/end sweep angles.
@@ -944,7 +944,7 @@ pub(crate) fn tapered_band_points(
         if bulge.abs() < 1e-9 {
             push(p1[0], p1[1], ew0 as f32);
         } else if let Some(arc) = BulgeArc::from_bulge(p0, p1, bulge) {
-            let samples = arc.tessellate_angle(cadkernel::tessellation::DEFAULT_ANGLE);
+            let samples = arc.tessellate_angle(kernel::tessellation::DEFAULT_ANGLE);
             let segments = samples.len().saturating_sub(1).max(1);
             for (index, s) in samples.into_iter().enumerate().skip(1) {
                 let t = index as f64 / segments as f64;
@@ -970,10 +970,10 @@ pub(crate) fn wide_band_outline(
     restart_per_segment: bool,
     to_wcs: &dyn Fn(f64, f64) -> (f64, f64, f64),
 ) -> WideBandOutline {
-    let source = cadkernel::geom2d::Polyline {
+    let source = kernel::geom2d::Polyline {
         vertices: verts
             .iter()
-            .map(|(position, bulge, _, _)| cadkernel::geom2d::PolylineVertex {
+            .map(|(position, bulge, _, _)| kernel::geom2d::PolylineVertex {
                 position: *position,
                 bulge: *bulge,
             })
@@ -990,10 +990,10 @@ pub(crate) fn wide_band_outline(
         .take(segment_count)
         .map(|(_, _, start, end)| [*start, *end])
         .collect();
-    let boundary = cadkernel::geom2d::polyline_band_boundary(
+    let boundary = kernel::geom2d::polyline_band_boundary(
         &source,
         &widths,
-        cadkernel::tessellation::DEFAULT_ANGLE,
+        kernel::tessellation::DEFAULT_ANGLE,
     );
     let mut points = Vec::new();
     let mut stations = Vec::new();