refactor: Engine updates and NX hooks improvements

optimization_engine:
- Updated nx_solver.py with improvements
- Enhanced solve_simulation.py
- Updated extractors/__init__.py
- Improved NX CAD hooks (expression_manager, feature_manager,
  geometry_query, model_introspection, part_manager)
- Enhanced NX CAE solver_manager hook

Documentation:
- Updated OP_01_CREATE_STUDY.md protocol
- Updated SYS_12_EXTRACTOR_LIBRARY.md

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Opus 4.5 <noreply@anthropic.com>

optimization_engine/extractors/__init__.py

@@ -10,6 +10,7 @@ Available extractors:
 - Strain Energy: extract_strain_energy, extract_total_strain_energy
 - SPC Forces: extract_spc_forces, extract_total_reaction_force
 - Zernike: extract_zernike_from_op2, ZernikeExtractor (telescope mirrors)
+- Part Introspection: introspect_part (comprehensive NX .prt analysis)
 
 Phase 2 Extractors (2025-12-06):
 - Principal stress extraction (sigma1, sigma2, sigma3)
@@ -21,6 +22,9 @@ Phase 3 Extractors (2025-12-06):
 - Thermal gradient extraction
 - Heat flux extraction
 - Modal mass extraction (modal effective mass from F06)
+
+Phase 4 Extractors (2025-12-19):
+- Part Introspection (E12): Comprehensive .prt analysis (expressions, mass, materials, attributes, groups, features)
 """
 
 # Zernike extractor for telescope mirror optimization
@@ -82,6 +86,14 @@ from optimization_engine.extractors.extract_modal_mass import (
     get_modal_mass_ratio,
 )
 
+# Part introspection (Phase 4) - comprehensive .prt analysis
+from optimization_engine.extractors.introspect_part import (
+    introspect_part,
+    get_expressions_dict,
+    get_expression_value,
+    print_introspection_summary,
+)
+
 __all__ = [
     # Part mass & material (from .prt)
     'extract_part_mass_material',
@@ -117,4 +129,9 @@ __all__ = [
     'extract_frequencies',
     'get_first_frequency',
     'get_modal_mass_ratio',
+    # Part introspection (Phase 4)
+    'introspect_part',
+    'get_expressions_dict',
+    'get_expression_value',
+    'print_introspection_summary',
 ]