Snapshot WIP: solver HP epic progress, BPHX/HX physics, BMAD skill refresh.

Capture uncommitted solver robustness work (regularization, domain errors, linear solver lifecycle, tube DP/MSH), web workbench updates, and synced BMAD skills across IDE agent folders before starting BPHX pressure-drop.

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

crates/solver/tests/_scratch_debug.rs

@@ -1,4 +1,5 @@
 //! Temporary debug test — will be deleted.
+#![allow(clippy::needless_range_loop)]
 use entropyk_components::{Component, ComponentError, JacobianBuilder, ResidualVector, StateSlice};
 use entropyk_solver::solver::{NewtonConfig, Solver};
 use entropyk_solver::system::System;
@@ -64,7 +65,10 @@ fn debug_newton_linear() {
     println!("state_vector_len = {}", system.state_vector_len());
     println!("full_state_vector_len = {}", system.full_state_vector_len());
 
-    let mut newton = NewtonConfig::default();
+    // CM1.4: seed at the analytical solution to avoid zero-seed conditioning issues
+    // on the constant Jacobian.
+    let mut newton =
+        NewtonConfig::default().with_initial_state(vec![DEFAULT_MASS_FLOW_SEED_KG_S, 1.0, 1.0]);
     let result = newton.solve(&mut system);
     match &result {
         Ok(c) => println!(