feat: Update environment.yml with PyTorch and add installation guide

- environment.yml: Added PyTorch with CUDA 12.1, PyG (torch-geometric),
  and TensorBoard for neural network training
- INSTALL_INSTRUCTIONS.md: Step-by-step guide for installing Miniconda
  and setting up the Atomizer environment

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

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

INSTALL_INSTRUCTIONS.md

@@ -0,0 +1,63 @@
+# Atomizer Installation Guide
+
+## Step 1: Install Miniconda (Recommended)
+
+1. Download Miniconda from: https://docs.conda.io/en/latest/miniconda.html
+   - Choose: **Miniconda3 Windows 64-bit**
+
+2. Run the installer:
+   - Check "Add Miniconda3 to my PATH environment variable"
+   - Check "Register Miniconda3 as my default Python"
+
+3. Restart your terminal/VSCode after installation
+
+## Step 2: Create Atomizer Environment
+
+Open **Anaconda Prompt** (or any terminal after restart) and run:
+
+```bash
+cd C:\Users\Antoine\Atomizer
+conda env create -f environment.yml
+conda activate atomizer
+```
+
+## Step 3: Install PyTorch with GPU Support (Optional but Recommended)
+
+If you have an NVIDIA GPU:
+
+```bash
+conda activate atomizer
+pip install torch torchvision torchaudio --index-url https://download.pytorch.org/whl/cu121
+pip install torch-geometric
+```
+
+## Step 4: Verify Installation
+
+```bash
+conda activate atomizer
+python -c "import torch; import optuna; import pyNastran; print('All imports OK!')"
+python -c "import torch; print(f'CUDA available: {torch.cuda.is_available()}')"
+```
+
+## Step 5: Train Neural Network
+
+```bash
+conda activate atomizer
+cd C:\Users\Antoine\Atomizer\atomizer-field
+python train_parametric.py --train_dir ../atomizer_field_training_data/bracket_stiffness_optimization_atomizerfield --epochs 100 --output_dir runs/bracket_model
+```
+
+## Quick Commands Reference
+
+```bash
+# Activate environment (do this every time you open a new terminal)
+conda activate atomizer
+
+# Train neural network
+cd C:\Users\Antoine\Atomizer\atomizer-field
+python train_parametric.py --train_dir ../atomizer_field_training_data/bracket_stiffness_optimization_atomizerfield --epochs 100
+
+# Run optimization with neural acceleration
+cd C:\Users\Antoine\Atomizer\studies\bracket_stiffness_optimization_atomizerfield
+python run_optimization.py --run --trials 100 --enable-nn
+```