Modernize package structure for better usability and maintainability

[jasonsethrothman]

Problem

pyNeuroMatic currently lacks modern Python package infrastructure.

First issue addressed here:

• ❌ GUI dependencies exist even for non-GUI users

Proposed Solution

Restructure pyNeuroMatic as follows:

pyNeuroMatic/
├── pyneuromatic/          # Main package (lowercase)
│   ├── core/             # Data structures, I/O
│   ├── analysis/         # Analysis algorithms  
│   ├── visualization/    # Matplotlib plots
│   └── gui/             # Optional GUI (separate)
├── tests/                # Automated tests
├── docs/                 # Sphinx documentation
├── examples/             # Jupyter notebooks
└── pyproject.toml        # Modern packaging

Key Changes

1. Separate GUI from Core

# Core: works without GUI
pip install pyneuromatic
import pyneuromatic as pnm
spikes = pnm.detect_spikes(data)

# GUI: optional
pip install pyneuromatic[gui]
pyneuromatic-gui

### Benefits

- ✅ Use without GUI on servers
- ✅ Clear code organization
- ✅ Easier to maintain
- ✅ Wider adoption

[jasonsethrothman]

✅ Completed in PR #8

Implemented:

• ✅ Separated GUI dependencies from core
• ✅ Added optional [gui] extra
• ✅ Modernized package structure
• ✅ Added CI/CD workflows
• ✅ Updated documentation

Package restructuring is complete