Add contributing guide with LLM quick start instructions

CONTRIBUTING.md

@@ -0,0 +1,120 @@
+# Contributing to Freighter Backend (V1)
+
+TypeScript backend service powering the Freighter wallet. Provides indexing,
+subscriptions, feature flags, notifications, token balances, and pricing data.
+
+For the Stellar organization's general contribution guidelines, see the
+[Stellar Contribution Guide](https://github.com/stellar/.github/blob/master/CONTRIBUTING.md).
+
+## Prerequisites
+
+| Tool   | Version   | Install                                                      |
+| ------ | --------- | ------------------------------------------------------------ |
+| Node.js | >= 25.3.0 | [nodejs.org](https://nodejs.org) or `nvm install 25`         |
+| Yarn   | >= 1.22.5 | `npm install --global yarn`                                  |
+| Docker | Latest    | [docker.com](https://docs.docker.com/get-docker/) (for Redis) |
+
+## Getting Started
+
+### Quick Setup with an LLM
+
+If you use an LLM-powered coding assistant, you can automate the setup. The repo
+includes a quick start guide ([`LLM-QUICK-START.md`](LLM-QUICK-START.md)) that
+checks your environment, installs missing tools, configures `.env`, and verifies
+the build.
+
+Point your LLM assistant at `LLM-QUICK-START.md` and ask it to follow the steps.
+
+If you don't use an LLM assistant, follow the manual setup below.
+
+### Manual Setup
+
+```bash
+git clone https://github.com/stellar/freighter-backend.git
+cd freighter-backend
+cp .env-EXAMPLE .env    # Then fill in values (see below)
+yarn install
+yarn start              # Dev mode (uses in-memory store, no Redis needed)
+```
+
+For production mode (requires Redis):
+
+```bash
+docker compose up -d    # Starts Redis Stack on port 6379
+yarn build:prod
+node build/index.js
+```
+
+### Environment Variables
+
+Copy `.env-EXAMPLE` to `.env`. For local development with `yarn start`, most
+variables can be left as `not-set` — the app uses an in-memory store by default.
+
+**Required for full functionality:**
+
+| Variable            | Purpose                                        | How to obtain                       |
+| ------------------- | ---------------------------------------------- | ----------------------------------- |
+| `MODE`              | `development` or `production`                  | Set to `development` for local dev  |
+| `HOSTNAME`          | Server hostname                                | `localhost`                         |
+| `REDIS_PORT`        | Redis port                                     | `6379` (Docker Compose default)     |
+| `REDIS_CONNECTION_NAME` | Redis connection name                      | Any string (e.g., `freighter-dev`)  |
+
+**Optional — features degrade gracefully:**
+
+| Variable              | Purpose                    | Notes                                |
+| --------------------- | -------------------------- | ------------------------------------ |
+| `AUTH_EMAIL` / `AUTH_PASS` | Mercury indexer auth    | Only needed if `USE_MERCURY=true`    |
+| `SENTRY_KEY`          | Error tracking             | Leave as `not-set` for local dev     |
+| `BLOCKAID_KEY`        | Transaction scanning       | Leave as `not-set` for local dev     |
+| `COINBASE_API_KEY/SECRET` | Pricing data           | Leave as `not-set` for local dev     |
+| `FREIGHTER_HORIZON_URL` | Stellar Horizon endpoint | Defaults to public Horizon if unset  |
+
+## Key Commands
+
+```bash
+yarn start              # Dev mode (in-memory store)
+yarn build:prod         # Production build (webpack)
+yarn test               # Jest unit tests
+yarn test:ci            # Jest CI mode
+```
+
+## Code Conventions
+
+- **Formatting:** Prettier + ESLint (extends `@stellar/eslint-config`)
+- **Pre-commit hooks:** `pretty-quick --staged` + `lint-staged` (ESLint fix)
+- **Framework:** Fastify v5 with CORS, Helmet, rate-limiting
+- **Logging:** Pino
+- **Monitoring:** Prometheus metrics via `prom-client`
+
+## Testing
+
+```bash
+yarn test               # Run all tests
+yarn test:ci            # CI mode
+```
+
+Jest with `ts-jest` preset, Node test environment.
+
+## Pull Requests
+
+- Branch from `main`
+- Commit messages: action verb in present tense
+- All tests must pass
+- Code must be formatted (pre-commit hooks handle this)
+
+**CI runs on every PR:** build + test (`runTests.yaml`).
+
+## Related Repositories
+
+- [stellar/freighter-backend-v2](https://github.com/stellar/freighter-backend-v2)
+  (Go) — V2 backend for collectibles, RPC health, protocols
+- [stellar/freighter](https://github.com/stellar/freighter) — Browser extension
+- [stellar/freighter-mobile](https://github.com/stellar/freighter-mobile) — Mobile app
+
+## Security
+
+- **Never log** API keys, auth credentials, or user data
+- **Rate limiting** is enforced via Fastify plugin — don't bypass
+- **Report vulnerabilities** via the
+  [Stellar Security Policy](https://github.com/stellar/.github/blob/master/SECURITY.md)
+  — not public issues

LLM-QUICK-START.md

@@ -0,0 +1,97 @@
+# Freighter Backend V1 — LLM Quick Start
+
+Evaluate the contributor's machine against all prerequisites for
+freighter-backend (TypeScript/Fastify), install what's missing, and run the
+initial setup.
+
+## Step 1: Check all prerequisites
+
+Run every check and collect results. Report all at once.
+
+```bash
+# Node.js >= 25.3.0
+node --version 2>&1 || which node
+
+# Yarn
+yarn --version 2>&1 || which yarn
+
+# Docker (needed for Redis in production mode)
+docker --version 2>&1 || which docker
+
+# Docker Compose
+docker compose version 2>&1 || which docker-compose
+```
+
+## Step 2: Present results
+
+```
+Freighter Backend V1 — Prerequisites Check
+============================================
+  Node.js        v25.x.x        >= 25.3.0 required   OK
+  Yarn           1.22.x         >= 1.22.5 required    OK
+  Docker         27.x.x         any (for Redis)       OK
+  Docker Compose 2.x.x          any                   OK
+```
+
+## Step 3: Install missing tools
+
+Present missing tools and ask the user to confirm before installing.
+
+**Auto-installable (run after user confirms):**
+
+- **nvm + Node.js 25**: `nvm install 25`
+- **Yarn**: `npm install --global yarn`
+- **Docker**: `brew install --cask docker` (macOS) or follow
+  [docs.docker.com](https://docs.docker.com/engine/install/) (Linux)
+
+## Step 4: Configure environment
+
+Check if `.env` exists. If not:
+
+```bash
+cp .env-EXAMPLE .env
+```
+
+For local development with `yarn start`, most values can stay as `not-set` — the
+app uses an in-memory store. Set these for basic operation:
+
+| Variable              | Value for local dev       |
+| --------------------- | ------------------------- |
+| `MODE`                | `development`             |
+| `HOSTNAME`            | `localhost`               |
+| `REDIS_PORT`          | `6379`                    |
+| `REDIS_CONNECTION_NAME` | `freighter-dev`         |
+
+## Step 5: Run initial setup
+
+```bash
+yarn install
+yarn start              # Dev mode with in-memory store
+```
+
+For production mode (requires Redis):
+
+```bash
+docker compose up -d    # Start Redis
+yarn build:prod
+node build/index.js
+```
+
+## Step 6: Verify
+
+```bash
+yarn test               # Jest unit tests
+```
+
+## Step 7: Summary
+
+```
+Setup Complete
+==============
+  Prerequisites: [list with versions]
+  Configured: .env from .env-EXAMPLE
+
+  Ready to run:
+  - yarn start           (dev mode, in-memory store)
+  - docker compose up -d (start Redis for production mode)
+```