feat: add adaptive isogrid tool — project foundations

- Python Brain: density field, constrained Delaunay triangulation,
  pocket profiles, profile assembly, validation modules
- NX Hands: skeleton scripts for geometry extraction, AFEM setup,
  per-iteration solve (require NX environment to develop)
- Atomizer integration: 15-param space definition, objective function
- Technical spec, README, sample test geometry, requirements.txt
- Architecture: Python Brain + NX Hands + Atomizer Manager

tools/adaptive-isogrid/src/nx/iteration_solve.py

@@ -0,0 +1,35 @@
+"""
+NXOpen script — Per-iteration Model B rebuild + solve + extract.
+
+LOOP: Called by Atomizer for each trial.
+1. Delete old Model B geometry + mesh
+2. Import new 2D ribbed profile from rib_profile.json
+3. Mesh with hard-point seeds at interface node locations
+4. Merge nodes in Assembly FEM
+5. Solve (Nastran)
+6. Extract results → results.json
+
+NOTE: Skeleton — requires NX environment for development.
+See docs/technical-spec.md Section 4.3 for full pseudocode.
+"""
+
+
+def iteration_solve(profile_path, interface_nodes_path, afem_part):
+    """
+    Single optimization iteration.
+    
+    Returns dict with status, mass, stress/displacement fields.
+    """
+    raise NotImplementedError(
+        "Develop inside NX Simcenter. See docs/technical-spec.md Section 4.3."
+    )
+
+
+def extract_results(afem, solution):
+    """
+    Extract field results from solved assembly FEM.
+    Only from Model B elements (plate mesh), ignoring spiders.
+    """
+    raise NotImplementedError(
+        "Develop inside NX Simcenter. See docs/technical-spec.md Section 4.3."
+    )