add service instructions

Author: keyleu

service/README.md

@@ -0,0 +1,50 @@
+# Prover Service
+
+gRPC service for generating SP1 Groth16 proofs for Ethereum light client updates and Hyperlane merkle roots.
+
+## Environment Variables
+
+Set the env variables in an .env file like the example provided.
+
+| Variable                | Required | Default | Description                                         |
+| ----------------------- | -------- | ------- | --------------------------------------------------- |
+| `ETH_BEACON_RPC`        | Yes      | -       | Ethereum Beacon Chain RPC endpoint                  |
+| `ETH_EXECUTION_RPC`     | Yes      | -       | Ethereum Execution Layer RPC endpoint               |
+| `NETWORK_PRIVATE_KEY`   | Yes      | -       | Private key for SP1 network prover authentication   |
+| `LIGHT_CLIENT_CONTRACT` | Yes      | -       | Address of the light client contract                |
+| `API_KEY`               | Yes      | -       | API key for authenticating requests to this service |
+| `CHAIN_ID`              | No       | `1`     | Chain ID (1 for Mainnet, 11155111 for Sepolia)      |
+| `PORT`                  | No       | `50051` | gRPC server port                                    |
+
+## Running the Service
+
+The service can be run either natively with Cargo or via Docker.
+
+### Native
+
+```bash
+cargo run --release
+```
+
+### Docker
+
+Build from project root:
+
+```bash
+docker build -t prover-service .
+```
+
+Run with environment variables in a `.env` file:
+
+```bash
+docker run --rm -p 50051:50051 --env-file .env --name prover prover-service
+```
+
+## Testing
+
+```bash
+grpcurl -plaintext \
+  -proto ./proto/prover.proto \
+  -H "x-api-key: $API_KEY" \
+  localhost:50051 proto.Prover/EthereumHyperlaneRoot
+```