docs: reset mitc4 formulation baseline

docs/NUMERICAL_CONVENTIONS.md

@@ -158,7 +158,7 @@ Phase 1 retains `RZ` at each shell node and assigns a small artificial drilling
 
 Rules:
 - The value must be parameterized, not hard-coded deep inside the MITC4 kernel.
-- The default value must be documented in `docs/MITC4_FORMULATION.md` before implementation.
+- The Phase 1 default follows `docs/MITC4_FORMULATION.md`: `drilling_stiffness_scale = 1.0e-3` applied to the minimum positive physical local stiffness diagonal before the local-to-global six-DOF transform.
 - The artificial stiffness should be small relative to representative membrane or bending stiffness, but large enough to avoid a singular stiffness matrix for unconstrained drilling modes.
 - Reference comparisons should include sensitivity checks if the drilling stiffness materially changes displacement results.
 
@@ -208,7 +208,7 @@ Before implementing solver modules that depend on numerical conventions:
 - Ensure singular diagnostics can reference node id, DOF component, element id, property id, and set name.
 
 ## Open Decisions
-- The exact default drilling stiffness scale.
-- The final MITC4 local basis algorithm for warped quadrilateral elements.
-- Which shell stress/strain/resultant outputs are mandatory in Phase 1.
+- Stress/strain/resultant recovery locations and component labels after `U` and `RF` are stable.
+- Whether to parse Abaqus `*Orientation` or nodal shell normals.
+- The future nodal-director policy for truly non-flat or strongly warped quadrilateral elements.
 - Optional non-displacement CSV formats, such as reaction force or stress/resultant exports.