feat: add OrderEvent, FilledEvent, SweepEvent type exports

[init4samwise]

Summary

Add typed event result interfaces for RollupOrders contract events to improve DX for indexers using viem's parseEventLogs.

Changes

• Create src/types/events.ts with OrderEvent, FilledEvent, SweepEvent interfaces
• Export types from src/types/index.ts and main src/index.ts
• Document viem parseEventLogs usage pattern in README
• Update CHANGELOG.md

Type Definitions

• OrderEvent: { deadline: bigint, inputs: readonly Input[], outputs: readonly Output[] }
• FilledEvent: { outputs: readonly Output[] }
• SweepEvent: { recipient: Address, token: Address, amount: bigint }

Usage Example

import { parseEventLogs } from 'viem';
import { rollupOrdersAbi, OrderEvent, FilledEvent, SweepEvent } from '@signet-sh/sdk';

const logs = parseEventLogs({ abi: rollupOrdersAbi, logs: receipt.logs });

for (const log of logs) {
  if (log.eventName === 'Order') {
    const args: OrderEvent = log.args;
    console.log('Order initiated:', args.deadline, args.inputs, args.outputs);
  }
}

Closes ENG-1893