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/benches/batch_solve.rs

@@ -0,0 +1,32 @@
+//! Phase-0 benchmark: sequential batch-solve scaling baseline.
+//!
+//! Solves N independent copies of the same reference cycle sequentially. This is
+//! the Phase-0 *sequential* baseline; any parallel batch path belongs to Epic 4
+//! and is intentionally out of scope here.
+
+use criterion::{black_box, criterion_group, criterion_main, BenchmarkId};
+
+mod common;
+
+fn bench_batch_sequential(c: &mut criterion::Criterion) {
+    let mut group = c.benchmark_group("batch_solve_sequential");
+    for n in [1, 2, 4] {
+        group.bench_with_input(BenchmarkId::from_parameter(n), &n, |b, &n| {
+            b.iter(|| {
+                for _ in 0..n {
+                    let mut system = common::build_reference_cycle_a();
+                    common::solve_reference_system(&mut system);
+                    black_box(());
+                }
+            });
+        });
+    }
+    group.finish();
+}
+
+criterion_group! {
+    name = benches;
+    config = common::end_to_end_criterion();
+    targets = bench_batch_sequential
+}
+criterion_main!(benches);