feat: add ERC2771 meta tx release note (#208)

## Summary by Sourcery

Add release notes for ERC-2771 meta-transactions integration, explaining
how the feature enables gas-less transactions on the SettleMint platform

New Features:
- Implement ERC-2771 meta-transactions support, allowing users to
interact with blockchain applications without paying gas fees
- Introduce a secure meta-transaction system using OpenZeppelin's
ERC2771Forwarder contract with EIP-712 signature validation

Documentation:
- Create comprehensive release notes detailing the ERC-2771
meta-transactions feature, including technical overview, key features,
implementation details, and potential use cases

---------

Co-authored-by: Roderik van der Veer <roderik@settlemint.com>

Author: daanporon

content/release-notes/assets/erc2771-diagram.png

@@ -0,0 +1,68 @@
+---
+title: "ERC-2771 Meta-Transactions Integration"
+description: "Release notes for the SettleMint ERC-2771 meta-transactions integration"
+date: "2025-04-07"
+author: "SettleMint"
+---
+
+# ERC-2771 Meta-Transactions Integration
+
+![Meta-Transactions Console](./assets/erc2771-platform.png)
+
+## Overview
+
+The SettleMint platform now supports ERC-2771 meta-transactions, enabling gas-less transactions for end users. With this integration, transaction fees can be covered by a designated relayer instead of the end user, significantly improving the user experience for blockchain applications. This implementation is based on [OpenZeppelin's ERC2771Forwarder contract](https://docs.openzeppelin.com/contracts/5.x/api/metatx), providing a secure and standardized approach to meta-transactions.
+
+## Key Features
+
+### Gas-less Transactions
+
+- **Fee Abstraction**: End users can interact with blockchain applications without holding native tokens for gas
+- **Improved Onboarding**: Remove the friction of acquiring tokens before using your application
+- **Enterprise-ready**: Ideal for business applications where users shouldn't be concerned with blockchain mechanics
+
+### Secure Implementation
+
+- **OpenZeppelin Standard**: Built on the battle-tested ERC2771Forwarder implementation
+- **EIP-712 Signatures**: Uses cryptographically secure typed data signatures
+- **Request Validation**: Comprehensive validation including deadline checks and nonce management
+
+### Seamless Integration
+
+- **Automatic Handling**: Our signer manages the complexity of meta-transactions behind the scenes
+- **Simple Configuration**: Easy setup process when creating private keys
+- **Cross-Contract Support**: Works with any contract that implements the ERC-2771 standard
+
+## Getting Started
+
+To enable meta-transactions for your private keys:
+
+1. When creating a new private key, enable the meta-transactions option
+2. Enter the Forwarder contract address
+3. Provide the name of the Forwarder contract
+4. Assign a relayer key that will pay the gas costs
+
+## How Meta-Transactions Work
+
+Meta-transactions allow users to interact with the blockchain without paying for gas. While the user experience remains simple, here's what happens behind the scenes in the SettleMint platform:
+
+1. The user sends a regular transaction to our transaction signer
+2. Our system detects that the private key is configured for meta-transactions
+3. A structured message is created and signed (using EIP-712) with the key of the user
+4. This message is wrapped inside a normal transaction that is signed by the relayer
+5. The transaction is sent to the Forwarder contract with the user's signed message as payload
+6. The Forwarder contract thoroughly validates the message, verifies the signature, prevents replay attacks through nonce tracking,
+7. If everything checks out it then forwards the call to the destination contract
+
+![Meta-Transactions Diagram](./assets/erc2771-diagram.png)
+
+All this complexity is managed by the SettleMint platform - you only need to enable the feature and assign a relayer. From the user's perspective, transactions work as normal but don't require gas.
+
+## Use Cases
+
+- **Consumer Applications**: Eliminate the need for users to purchase crypto before using your dApp
+- **Enterprise Solutions**: Allow employees to interact with blockchain applications without managing tokens
+- **Gaming & NFTs**: Enable in-game purchases and NFT minting without interrupting gameplay
+- **Identity & Governance**: Facilitate voting and credential management without gas concerns
+- **Web2-like UX**: Create familiar user experiences that hide blockchain complexity
+