feat: Add AtomizerField training data export and intelligent model discovery

Major additions:
- Training data export system for AtomizerField neural network training
- Bracket stiffness optimization study with 50+ training samples
- Intelligent NX model discovery (auto-detect solutions, expressions, mesh)
- Result extractors module for displacement, stress, frequency, mass
- User-generated NX journals for advanced workflows
- Archive structure for legacy scripts and test outputs
- Protocol documentation and dashboard launcher

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

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

archive/test_scripts/test_backend.md

@@ -0,0 +1,74 @@
+# Backend Testing Guide
+
+## 1. Start Backend Server
+
+```bash
+cd atomizer-dashboard/backend
+python -m uvicorn api.main:app --reload --port 8000
+```
+
+## 2. Test REST Endpoints
+
+### Get Study Status
+```bash
+curl http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/status
+```
+
+### Get Pareto Front
+```bash
+curl http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/pareto-front
+```
+
+### Get Trial History
+```bash
+curl http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/trials
+```
+
+### Generate HTML Report
+```bash
+curl -X POST "http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/generate-report?format=html"
+```
+
+### List Studies
+```bash
+curl http://localhost:8000/api/optimization/studies
+```
+
+## 3. Test WebSocket (Browser Console)
+
+Open browser to `http://localhost:8000` and run in console:
+
+```javascript
+const ws = new WebSocket('ws://localhost:8000/api/ws/optimization/bracket_stiffness_optimization_V3');
+
+ws.onmessage = (event) => {
+  const data = JSON.parse(event.data);
+  console.log('Received:', data);
+};
+
+ws.onopen = () => console.log('Connected to optimization stream');
+ws.onerror = (error) => console.error('WebSocket error:', error);
+```
+
+You should see a `connected` message with current trial count.
+
+## 4. Test Mesh Conversion (If Nastran Files Available)
+
+```bash
+curl -X POST http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/convert-mesh
+```
+
+## 5. Download Generated Report
+
+After generating report, download it:
+```bash
+curl http://localhost:8000/api/optimization/studies/bracket_stiffness_optimization_V3/reports/optimization_report.html -o test_report.html
+```
+
+## Expected Results
+
+- **Status endpoint**: Should return study config, trial counts, best values
+- **Pareto front**: Should return 48 Pareto-optimal solutions
+- **Trials endpoint**: Should return all 100 trial records
+- **Report generation**: Should create HTML file in `studies/bracket_stiffness_optimization_V3/2_results/reports/`
+- **WebSocket**: Should show connected message with current_trials = 100