Snapshot WIP: Probe calibration path, faer LU backend, and BPHX phase-change duty.

Checkpoint incomplete calibration work (cond SDT green, evap SST failing) plus related solver/UI changes so the next pass can fix and extend safely.

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

_bmad-output/implementation-artifacts/sprint-status.yaml

@@ -26,14 +26,14 @@
 # - Dev moves story to 'review', then Dev runs code-review (fresh context, ideally different LLM)
 
 generated: 2026-07-18T12:51:31Z
-last_updated: 2026-07-19T14:40:00Z
+last_updated: 2026-07-19T16:00:00Z
 project: Entropyk
-project_key: ENTROPYK
+project_key: ENTROPYKnon 
 tracking_system: file-system
 story_location: "{project-root}/_bmad-output/implementation-artifacts"
 
 development_status:
-  epic-0: done
+  epic-0: in-progress
   0-1-fix-failing-tests: done
   epic-0-retrospective: optional
   # --- Epic 0: Physical Regularization & Jacobian Health (epics-solver-hp.md) ---
@@ -42,8 +42,8 @@ development_status:
   0-3-valve-flow-exv-regularization: done
   0-4-heat-exchanger-regularization: done
   0-5-domain-sweep-jacobian-health-gate: done
-  0-6-emergent-pressure-seed-robustness: review
   0-7-bphx-property-call-reduction: review
+  0-8-bphx-phase-change-entu-duty: review
   # --- Epic 1: Performance Foundation - Linear Algebra Modernization ---
   epic-1: in-progress
   1-1-phase-0-baseline-golden-safety-net: review