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>

optimization_engine/core/__init__.py

@@ -0,0 +1,64 @@
+"""
+Optimization Engine Core
+========================
+
+Main optimization runners and algorithm selection.
+
+Modules:
+- runner: Main OptimizationRunner class
+- base_runner: BaseRunner abstract class
+- intelligent_optimizer: IMSO adaptive optimizer
+- method_selector: Algorithm selection logic
+- strategy_selector: Strategy portfolio management
+"""
+
+# Lazy imports to avoid circular dependencies
+def __getattr__(name):
+    if name == 'OptimizationRunner':
+        from .runner import OptimizationRunner
+        return OptimizationRunner
+    elif name == 'BaseRunner':
+        from .base_runner import BaseRunner
+        return BaseRunner
+    elif name == 'NeuralOptimizationRunner':
+        from .runner_with_neural import NeuralOptimizationRunner
+        return NeuralOptimizationRunner
+    elif name == 'IntelligentOptimizer':
+        from .intelligent_optimizer import IntelligentOptimizer
+        return IntelligentOptimizer
+    elif name == 'IMSO':
+        from .intelligent_optimizer import IMSO
+        return IMSO
+    elif name == 'MethodSelector':
+        from .method_selector import MethodSelector
+        return MethodSelector
+    elif name == 'select_method':
+        from .method_selector import select_method
+        return select_method
+    elif name == 'StrategySelector':
+        from .strategy_selector import StrategySelector
+        return StrategySelector
+    elif name == 'StrategyPortfolio':
+        from .strategy_portfolio import StrategyPortfolio
+        return StrategyPortfolio
+    elif name == 'GradientOptimizer':
+        from .gradient_optimizer import GradientOptimizer
+        return GradientOptimizer
+    elif name == 'LBFGSPolisher':
+        from .gradient_optimizer import LBFGSPolisher
+        return LBFGSPolisher
+    raise AttributeError(f"module 'optimization_engine.core' has no attribute '{name}'")
+
+__all__ = [
+    'OptimizationRunner',
+    'BaseRunner',
+    'NeuralOptimizationRunner',
+    'IntelligentOptimizer',
+    'IMSO',
+    'MethodSelector',
+    'select_method',
+    'StrategySelector',
+    'StrategyPortfolio',
+    'GradientOptimizer',
+    'LBFGSPolisher',
+]