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>

docs/components/economizer.md

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+# Economizer (internal)
+
+Source: economizer HX used inside screw-economizer circuits (`HeatExchanger<LmtdModel>` patterns)
+
+---
+
+## EN
+
+### Purpose & model
+
+Internal heat exchanger that subcools liquid / evaporates injection gas for economized screw cycles. Often **not** a standalone CLI leaf — instantiated inside compressor economizer plumbing or macro components.
+
+Model: LMTD or ε-NTU between liquid line and eco vapor.
+
+### Residuals
+
+Standard two-stream HX residuals of the inner model.
+
+### Ports
+
+Hot/cold legs as wired by the parent circuit.
+
+### Note
+
+For user-facing machines, configure economizer via **ScrewEconomizerCompressor** + circuit topology rather than a free-floating Economizer node unless the CLI arm exposes it.
+
+---
+
+## FR
+
+### But
+
+Échangeur **économiseur** interne (sous-refroidissement / injection).
+
+### Note
+
+Souvent intégré au circuit vis, pas un composant CLI autonome.