docs: align consolidated solver workflow

phases/linear-static-3d-euler-beam/step0.md

@@ -17,7 +17,7 @@
 - `/docs/SOLVER_AGENT_DESIGN.md`
 - `/docs/requirements/README.md`
 - `/docs/superpowers/specs/2026-08-08-linear-static-3d-euler-beam-design.md`
-- `/docs/formulations/3d-isoparametric-euler-beam-formulation.md`
+- `/docs/linear-static-3d-euler-beam/formulation.md`
 - `/reference/cantilever beam/cantilever beam.inp`
 
 승인된 설계 문서의 `status: approved`와 2026-08-09 amendment를 이 step의 사용자 승인
@@ -25,7 +25,7 @@
 
 ## 작업
 
-`docs/requirements/linear-static-3d-euler-beam.md`를 생성하라. 문서는 다음 계약을
+`docs/linear-static-3d-euler-beam/requirements.md`를 생성하라. 문서는 다음 계약을
 downstream agent가 추측 없이 사용할 수 있는 `shall` 요구조건과 검증 행렬로 바꿔야 한다.
 
 - Metadata: `feature_id: linear-static-3d-euler-beam`, `status: approved`,
@@ -56,7 +56,7 @@ downstream agent가 추측 없이 사용할 수 있는 `shall` 요구조건과
 ## Acceptance Criteria
 
 ```powershell
-$path = 'docs/requirements/linear-static-3d-euler-beam.md'
+$path = 'docs/linear-static-3d-euler-beam/requirements.md'
 if (-not (Test-Path $path)) { throw "Missing $path" }
 $required = @(
   'feature_id: `linear-static-3d-euler-beam`',