feat: Merge Atomizer-Field neural network module into main repository

Permanently integrates the Atomizer-Field GNN surrogate system:
- neural_models/: Graph Neural Network for FEA field prediction
- batch_parser.py: Parse training data from FEA exports
- train.py: Neural network training pipeline
- predict.py: Inference engine for fast predictions

This enables 600x-2200x speedup over traditional FEA by replacing
expensive simulations with millisecond neural network predictions.

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

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

atomizer-field/neural_models/__init__.py

@@ -0,0 +1,10 @@
+"""
+AtomizerField Neural Models Package
+
+Phase 2: Neural Network Architecture for Field Prediction
+
+This package contains neural network models for learning complete FEA field results
+from mesh geometry, boundary conditions, and loads.
+"""
+
+__version__ = "2.0.0"