Add docs on how to run Flashblocks (#331)

* Add flashblocks docs

* Update docs

* Update docs/flashblocks.md

Co-authored-by: shana <[email protected]>

---------

Co-authored-by: shana <[email protected]>

Author: ferranbt

docs/flashblocks.md

@@ -0,0 +1,142 @@
+# Flashblocks
+
+Flashblocks is a feature in rollup-boost that enables pre-confirmations by proposing incremental sections of blocks. This guide walks you through setting up a complete Flashblocks environment with rollup-boost, op-rbuilder, and a fallback builder.
+
+## Overview
+
+The setup consists of three main components:
+
+- **rollup-boost**: The main service with Flashblocks enabled
+- **op-rbuilder**: A builder with Flashblocks support
+- **op-reth**: A fallback builder (standard EL node)
+
+## Prerequisites
+
+- Rust toolchain installed
+- Access to the rollup-boost and op-rbuilder repositories
+
+## Setup Instructions
+
+### 1. Start rollup-boost with Flashblocks
+
+Launch rollup-boost with Flashblocks enabled:
+
+```bash
+cargo run --bin rollup-boost -- \
+  --l2-url http://localhost:5555 \
+  --builder-url http://localhost:4445 \
+  --l2-jwt-token 688f5d737bad920bdfb2fc2f488d6b6209eebda1dae949a8de91398d932c517a \
+  --builder-jwt-token 688f5d737bad920bdfb2fc2f488d6b6209eebda1dae949a8de91398d932c517a \
+  --rpc-port 4444 \
+  --flashblocks \
+  --log-level info
+```
+
+This command uses the default Flashblocks configuration. For custom configurations, see the [Flashblocks Configuration](#flashblocks-configuration) section below.
+
+### 2. Generate Genesis Configuration
+
+Navigate to the op-rbuilder directory and create a genesis file:
+
+```bash
+cd op-rbuilder
+cargo run -p op-rbuilder --bin tester --features testing -- genesis > genesis.json
+```
+
+### 3. Start the op-rbuilder
+
+Launch op-rbuilder with Flashblocks enabled using the generated genesis file:
+
+```bash
+cargo run --bin op-rbuilder -- node \
+  --chain genesis.json \
+  --datadir data-builder \
+  --port 3030 \
+  --flashblocks.enabled \
+  --disable-discovery \
+  --authrpc.port 4445 \
+  --authrpc.jwtsecret ./crates/op-rbuilder/src/tests/framework/artifacts/test-jwt-secret.txt \
+  --http
+```
+
+**Note**: The JWT token is located at `./crates/op-rbuilder/src/tests/framework/artifacts/test-jwt-secret.txt` and matches the configuration used in rollup-boost.
+
+### 4. Start the Fallback Builder
+
+Launch op-reth as a fallback builder:
+
+```bash
+op-reth node \
+  --chain genesis.json \
+  --datadir one \
+  --port 3131 \
+  --authrpc.port 5555 \
+  --disable-discovery \
+  --authrpc.jwtsecret ./crates/op-rbuilder/src/tests/framework/artifacts/test-jwt-secret.txt
+```
+
+This runs a standard op-reth execution layer node that serves as the fallback builder for rollup-boost.
+
+### 5. Simulate the Consensus Layer
+
+Use the built-in tester utility to simulate a consensus layer node:
+
+```bash
+cargo run -p op-rbuilder --bin tester --features testing -- run
+```
+
+## Configuration Details
+
+### Port Configuration
+
+- `4444`: rollup-boost RPC port
+- `4445`: op-rbuilder auth RPC port (matches rollup-boost builder URL)
+- `5555`: op-reth auth RPC port (matches rollup-boost L2 URL)
+- `3030`: op-rbuilder P2P port
+- `3131`: op-reth P2P port
+
+### Flashblocks Configuration
+
+rollup-boost provides several configuration options for Flashblocks functionality:
+
+#### Basic Flashblocks Flag
+
+- `--flashblocks`: Enable Flashblocks client (required)
+  - Environment variable: `FLASHBLOCKS`
+
+#### WebSocket Connection Settings
+
+- `--flashblocks-builder-url <URL>`: Flashblocks Builder WebSocket URL
+
+  - Environment variable: `FLASHBLOCKS_BUILDER_URL`
+  - Default: `ws://127.0.0.1:1111`
+
+- `--flashblocks-host <HOST>`: Flashblocks WebSocket host for outbound connections
+
+  - Environment variable: `FLASHBLOCKS_HOST`
+  - Default: `127.0.0.1`
+
+- `--flashblocks-port <PORT>`: Flashblocks WebSocket port for outbound connections
+  - Environment variable: `FLASHBLOCKS_PORT`
+  - Default: `1112`
+
+#### Connection Management
+
+- `--flashblock-builder-ws-reconnect-ms <MILLISECONDS>`: Timeout duration if builder disconnects
+  - Environment variable: `FLASHBLOCK_BUILDER_WS_RECONNECT_MS`
+  - No default value specified
+
+#### Example with Custom Configuration
+
+```bash
+cargo run --bin rollup-boost -- \
+  --l2-url http://localhost:5555 \
+  --builder-url http://localhost:4445 \
+  --rpc-port 4444 \
+  --flashblocks \
+  --flashblocks-builder-url ws://localhost:9999 \
+  --flashblocks-host 0.0.0.0 \
+  --flashblocks-port 2222 \
+  --flashblock-builder-ws-reconnect-ms 5000 \
+  --log-level info
+```