feat: rich evolution demo, neuron tooltips, professional README

Evolution Mode (fully functional in demo):
- Client-side evolution simulation with realistic fitness curves
  (83 → 92 over 100 generations with noise and breakthroughs)
- God Agent mock interventions at gen 15, 40, 75
- Real-time streaming at 500ms/generation
- Population stats: species, synapse count, topology changes
- Pause/resume works correctly

3D Neuron Tooltips:
- Hover over neuron points → tooltip with name, type, NT, firing rate
- Raycasting on Points geometry via R3F onPointerMove
- HTML overlay positioned at mouse cursor
- Gene expression data shown when available
- HoveredNeuron state in simulationStore

Professional README:
- CI/License/Python/TypeScript/Tests badges
- Architecture diagram + directory tree
- Quick start (3 commands), Python API examples
- Scientific validation table (5 behaviors, 75% accuracy)
- Data sources, API reference, tech stack tables
- 6 paper references with DOIs
- CONTRIBUTING.md with setup + coding standards

183 tests passing, zero TypeScript errors.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

Author: masonwyatt23

CONTRIBUTING.md

@@ -0,0 +1,150 @@
+# Contributing to Neurevo
+
+Thank you for your interest in contributing to Neurevo. This document outlines the process for contributing to the project.
+
+## Getting Started
+
+1. Fork the repository and clone your fork:
+
+```bash
+git clone https://github.com/<your-username>/creatures.git
+cd creatures
+```
+
+2. Set up the development environment:
+
+```bash
+make setup
+```
+
+3. Run the test suite to verify everything works:
+
+```bash
+make test
+```
+
+## Development Workflow
+
+1. Create a feature branch from `main`:
+
+```bash
+git checkout -b feature/your-feature-name
+```
+
+2. Make your changes, following the coding standards below.
+
+3. Run tests and ensure they pass:
+
+```bash
+# Python tests
+make test
+
+# Frontend tests (if you modified creatures-web)
+cd creatures-web && npm test
+```
+
+4. Commit your changes with a clear message:
+
+```bash
+git commit -m "Add description of what changed and why"
+```
+
+5. Push to your fork and open a pull request against `main`.
+
+## Coding Standards
+
+### Python (creatures-core, creatures-api)
+
+- Python 3.13+
+- Follow PEP 8 style guidelines
+- Use type hints for function signatures
+- Write docstrings for public functions and classes
+- Keep functions focused -- one function, one responsibility
+- Add unit tests for new functionality in `creatures-core/tests/`
+
+### TypeScript (creatures-web)
+
+- TypeScript strict mode
+- Use functional components with hooks
+- Keep components small and composable
+- Use Zustand for shared state, not prop drilling
+
+### General
+
+- No committed secrets, API keys, or credentials
+- Keep dependencies minimal -- justify new additions
+- Write clear commit messages that explain *why*, not just *what*
+
+## Project Structure
+
+| Directory | Language | Purpose |
+|-----------|----------|---------|
+| `creatures-core/` | Python | Core library: connectome, neural simulation, evolution, pharmacology |
+| `creatures-api/` | Python | FastAPI server with REST and WebSocket endpoints |
+| `creatures-web/` | TypeScript | React + Three.js frontend |
+| `scripts/` | Python | CLI tools for evolution, validation, and reporting |
+| `notebooks/` | Jupyter | Interactive demos and exploration |
+
+## Where to Contribute
+
+### High-Impact Areas
+
+- **New organisms**: Add connectome loaders and body models for zebrafish, mouse, or other species
+- **Neuron models**: Implement Hodgkin-Huxley or multi-compartment models alongside the existing LIF engine
+- **Fitness functions**: Design new behavioral assays for evolution (foraging efficiency, learning tasks, social behavior)
+- **Performance**: Optimize Brian2 simulation speed, parallelize evolution runs, GPU acceleration
+- **Pharmacology**: Add new drug models with receptor-level specificity
+- **Visualization**: Improve 3D rendering, add connectome graph views, evolution dashboards
+
+### Good First Issues
+
+Look for issues labeled `good first issue` on GitHub. These are scoped tasks suitable for new contributors.
+
+## Testing
+
+All contributions should include tests where applicable.
+
+```bash
+# Run Python tests with verbose output
+python -m pytest creatures-core/tests/ -v
+
+# Run a specific test file
+python -m pytest creatures-core/tests/test_connectome.py -v
+
+# Run with coverage
+python -m pytest creatures-core/tests/ --cov=creatures --cov-report=term-missing
+```
+
+## Pull Request Guidelines
+
+- Keep PRs focused on a single change
+- Include a clear description of what changed and why
+- Reference any related issues
+- Ensure CI passes before requesting review
+- Add tests for new functionality
+- Update documentation if the public API changes
+
+## Reporting Bugs
+
+Open a GitHub issue with:
+
+1. A clear title describing the bug
+2. Steps to reproduce
+3. Expected behavior vs. actual behavior
+4. Your environment (OS, Python version, relevant package versions)
+
+## Requesting Features
+
+Open a GitHub issue with the `enhancement` label. Include:
+
+1. The problem you are trying to solve
+2. Your proposed solution
+3. Any alternatives you considered
+
+## Code of Conduct
+
+Be respectful and constructive. We are building tools to advance neuroscience and reduce animal testing. Treat fellow contributors with the same care we bring to the science.
+
+## License
+
+By contributing, you agree that your contributions will be licensed under the MIT License.