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/study/history_generator.py

@@ -0,0 +1,69 @@
+"""
+Generate history.json from trial directories.
+
+For older substudies that don't have history.json,
+reconstruct it from individual trial results.json files.
+"""
+
+from pathlib import Path
+import json
+import sys
+
+
+def generate_history(substudy_dir: Path) -> list:
+    """Generate history from trial directories."""
+    substudy_dir = Path(substudy_dir)
+    trial_dirs = sorted(substudy_dir.glob('trial_*'))
+
+    history = []
+
+    for trial_dir in trial_dirs:
+        results_file = trial_dir / 'results.json'
+
+        if not results_file.exists():
+            print(f"Warning: No results.json in {trial_dir.name}")
+            continue
+
+        with open(results_file, 'r') as f:
+            trial_data = json.load(f)
+
+        # Extract trial number from directory name
+        trial_num = int(trial_dir.name.split('_')[-1])
+
+        # Create history entry
+        history_entry = {
+            'trial_number': trial_num,
+            'timestamp': trial_data.get('timestamp', ''),
+            'design_variables': trial_data.get('design_variables', {}),
+            'objectives': trial_data.get('objectives', {}),
+            'constraints': trial_data.get('constraints', {}),
+            'total_objective': trial_data.get('total_objective', 0.0)
+        }
+
+        history.append(history_entry)
+
+    # Sort by trial number
+    history.sort(key=lambda x: x['trial_number'])
+
+    return history
+
+
+if __name__ == '__main__':
+    if len(sys.argv) < 2:
+        print("Usage: python generate_history_from_trials.py <substudy_directory>")
+        sys.exit(1)
+
+    substudy_path = Path(sys.argv[1])
+
+    print(f"Generating history.json from trials in: {substudy_path}")
+
+    history = generate_history(substudy_path)
+
+    print(f"Generated {len(history)} history entries")
+
+    # Save history.json
+    history_file = substudy_path / 'history.json'
+    with open(history_file, 'w') as f:
+        json.dump(history, f, indent=2)
+
+    print(f"Saved: {history_file}")