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>

.agent/skills/bmad-spec/assets/headless-schemas.md

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+# Headless JSON Response
+
+The default invocation is headless: input goes in, JSON comes out. The contract is intentionally tiny — return the outcome and the files touched. Anything else a caller needs is inside those files (SPEC.md, companions, `.memlog.md`).
+
+## Success
+
+```json
+{
+  "status": "complete",
+  "files": [
+    "_bmad-output/specs/spec-quarter-drop/SPEC.md",
+    "_bmad-output/specs/spec-quarter-drop/glossary.md",
+    "_bmad-output/specs/spec-quarter-drop/.memlog.md"
+  ]
+}
+```
+
+`files` lists every file written or modified in this run, in any order. The spec folder, kernel filename, memlog location, capabilities, companions, and verdict are all readable from those files; no need to re-encode them in the response.
+
+## Blocked
+
+```json
+{
+  "status": "blocked",
+  "error_code": "insufficient_intent",
+  "reason": "Input was a one-line idea with no surrounding context; too thin to distill. Suggest bmad-prd to draw the vision out first."
+}
+```
+
+Defined `error_code` values:
+
+- `insufficient_intent` — input too thin to distill into a kernel.
+- `missing_slug` — input is sparse or multi-source and no slug was provided by the caller or derivable from a source path.