Add diagram workbench UI with Modelica DoF coaching and ISO glyphs.

Ship the Next.js cycle editor with CAD chrome, technical HX symbols, Fixed/Free boundary guidance, and secondary water/air pressure drop support in the solver stack.

Co-authored-by: Cursor <cursoragent@cursor.com>

crates/solver/tests/_scratch_debug.rs

@@ -0,0 +1,79 @@
+//! Temporary debug test — will be deleted.
+use entropyk_components::{Component, ComponentError, JacobianBuilder, ResidualVector, StateSlice};
+use entropyk_solver::solver::{NewtonConfig, Solver};
+use entropyk_solver::system::System;
+use entropyk_solver::system::DEFAULT_MASS_FLOW_SEED_KG_S;
+
+struct LinearSystem {
+    a: Vec<Vec<f64>>,
+    b: Vec<f64>,
+    n: usize,
+}
+
+impl Component for LinearSystem {
+    fn compute_residuals(
+        &self,
+        state: &StateSlice,
+        residuals: &mut ResidualVector,
+    ) -> Result<(), ComponentError> {
+        for i in 0..self.n {
+            let mut ax_i = 0.0;
+            for j in 0..self.n {
+                ax_i += self.a[i][j] * state[1 + j];
+            }
+            residuals[i] = ax_i - self.b[i];
+        }
+        residuals[self.n] = state[0] - DEFAULT_MASS_FLOW_SEED_KG_S;
+        Ok(())
+    }
+
+    fn jacobian_entries(
+        &self,
+        _state: &StateSlice,
+        jacobian: &mut JacobianBuilder,
+    ) -> Result<(), ComponentError> {
+        for i in 0..self.n {
+            for j in 0..self.n {
+                jacobian.add_entry(i, 1 + j, self.a[i][j]);
+            }
+        }
+        jacobian.add_entry(self.n, 0, 1.0);
+        Ok(())
+    }
+
+    fn n_equations(&self) -> usize {
+        self.n + 1
+    }
+
+    fn get_ports(&self) -> &[entropyk_components::ConnectedPort] {
+        &[]
+    }
+}
+
+#[test]
+fn debug_newton_linear() {
+    let mut system = System::new();
+    let n0 = system.add_component(Box::new(LinearSystem {
+        a: vec![vec![2.0, 1.0], vec![1.0, 2.0]],
+        b: vec![3.0, 3.0],
+        n: 2,
+    }));
+    system.add_edge(n0, n0).unwrap();
+    system.finalize().unwrap();
+
+    println!("state_vector_len = {}", system.state_vector_len());
+    println!("full_state_vector_len = {}", system.full_state_vector_len());
+
+    let mut newton = NewtonConfig::default();
+    let result = newton.solve(&mut system);
+    match &result {
+        Ok(c) => println!(
+            "OK: converged={} iters={} residual={}",
+            c.is_converged(),
+            c.iterations,
+            c.final_residual
+        ),
+        Err(e) => println!("ERR: {:?}", e),
+    }
+    assert!(result.is_ok());
+}