Add repo navigation guide

AGENTS.md

@@ -0,0 +1,37 @@
+# Repo Navigation Guide
+
+This repository contains the AR.IO gateway node written primarily in **TypeScript**.
+The codebase follows a conventional layout:
+
+- `src/` – main application source files.
+- `test/` – end-to-end and unit tests.
+- `features/` – cucumber feature files and step definitions.
+- `docs/` – documentation and diagrams.
+- `migrations/` – SQL migration scripts.
+- `scripts/` – helper shell scripts.
+- `docker-compose.yaml` – compose stack for development.
+
+## Development
+
+- Install dependencies with **Yarn** (`yarn install`). Node 20 is expected (`.nvmrc`).
+- Build the project with `yarn build`.
+- Run the service in development via `yarn start`.
+
+## Testing
+
+- Lint source and tests using `yarn lint:check`; auto-fix issues with `yarn lint:fix`.
+- Unit and integration tests run with `yarn test`. Coverage uses `yarn test:ci`.
+- End-to-end tests (Docker based) run with `yarn test:e2e`.
+- Cucumber feature tests run with `yarn test:features`.
+
+## Style
+
+- Prettier enforces 2‑space indent, single quotes and trailing commas (`.prettierrc`).
+- ESLint configuration requires the license header from `resources/license.header.js` at the top of source files.
+
+## Misc
+
+- Environment variables for configuration are documented in `docs/envs.md`.
+- Release workflow notes are in `docs/release-process.md`.
+- Diagram generation targets live in `Makefile`.
+