docs: add CONTRIBUTING.md to guide new contributors

Author: rishhbh

CONTRIBUTING.md

@@ -0,0 +1,70 @@
+# Contributing to LayerZero
+
+Thanks for checking out LayerZero! This is an actively maintained personal project, and contributions, bug reports, and suggestions are welcome.
+
+## Tech Stack
+
+Before diving in, make sure you're familiar with:
+- **Backend:** Node.js / Express (TypeScript)
+- **Caching:** Redis (via Upstash)
+- **Deployment:** Docker + GitHub Actions CI/CD, AWS EC2
+- **Frontend:** Cloudflare Workers
+- **AI Models:** Gemini, Cerebras GPT-OSS-120B, Gemma, Sarvam 30B (routed via a shared model interface)
+
+## Getting Started
+
+1. Fork the repo and clone your fork:
+   ```bash
+   git clone https://github.com/<your-username>/layerzero.git
+   cd layerzero
+   ```
+2. Install dependencies:
+   ```bash
+   npm install
+   ```
+3. Copy the example env file and fill in your own API keys:
+   ```bash
+   cp .env.example .env
+   ```
+4. Run locally:
+   ```bash
+   npm run dev
+   ```
+
+If you're using Docker instead:
+```bash
+docker compose up --build
+```
+
+## Making Changes
+
+1. Create a new branch off `main`:
+   ```bash
+   git checkout -b fix/short-description
+   ```
+2. Keep changes focused — one fix or feature per PR makes review much faster.
+3. Match the existing code style (TypeScript strict mode, existing naming conventions).
+4. Test your changes locally before opening a PR. If you're touching model routing, caching, or the ingestion pipeline, please note what you tested manually in the PR description (automated test coverage is still a work in progress).
+
+## Submitting a Pull Request
+
+1. Push your branch and open a PR against `main`.
+2. In the PR description, include:
+   - What the change does and why
+   - Any relevant screenshots/logs if it's a bug fix
+   - Whether it touches deployment config (Dockerfile, GitHub Actions workflows) — these get extra scrutiny since they affect the live EC2 deployment
+3. Be responsive to review comments — this is a small project maintained solo, so turnaround might take a few days.
+
+## Reporting Bugs / Suggesting Features
+
+Open an issue with:
+- **Bugs:** steps to reproduce, expected vs actual behavior, relevant logs
+- **Features:** what problem it solves, and if possible, a rough idea of implementation
+
+## Code of Conduct
+
+Be respectful, be constructive. This is a learning project as much as anything else — good-faith questions and beginner contributions are just as welcome as advanced ones.
+
+## Questions?
+
+Open an issue or start a discussion — happy to help you get oriented in the codebase.