refactor: Major reorganization of optimization_engine module structure

BREAKING CHANGE: Module paths have been reorganized for better maintainability.
Backwards compatibility aliases with deprecation warnings are provided.

New Structure:
- core/           - Optimization runners (runner, intelligent_optimizer, etc.)
- processors/     - Data processing
  - surrogates/   - Neural network surrogates
- nx/             - NX/Nastran integration (solver, updater, session_manager)
- study/          - Study management (creator, wizard, state, reset)
- reporting/      - Reports and analysis (visualizer, report_generator)
- config/         - Configuration management (manager, builder)
- utils/          - Utilities (logger, auto_doc, etc.)
- future/         - Research/experimental code

Migration:
- ~200 import changes across 125 files
- All __init__.py files use lazy loading to avoid circular imports
- Backwards compatibility layer supports old import paths with warnings
- All existing functionality preserved

To migrate existing code:
  OLD: from optimization_engine.nx_solver import NXSolver
  NEW: from optimization_engine.nx.solver import NXSolver

  OLD: from optimization_engine.runner import OptimizationRunner
  NEW: from optimization_engine.core.runner import OptimizationRunner

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

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

atomizer_paths.py

@@ -55,7 +55,7 @@ def setup_python_path():
     """
     Add Atomizer root to Python path if not already present.
 
-    This allows imports like `from optimization_engine.runner import ...`
+    This allows imports like `from optimization_engine.core.runner import ...`
     to work from anywhere in the project.
     """
     root = get_atomizer_root()
@@ -124,7 +124,7 @@ def ensure_imports():
     atomizer_paths.ensure_imports()
 
     # Now you can import Atomizer modules
-    from optimization_engine.runner import OptimizationRunner
+    from optimization_engine.core.runner import OptimizationRunner
     ```
     """
     setup_python_path()