[Docs] Add Code Examples for lib/money.ts Integer-Cents Calculations

• Labels: good first issue, documentation, difficulty:beginner, area:core
• Target File: docs/DEVELOPMENT.md
• Estimated Time: 5–10 minutes
• Difficulty: Level 1 (Beginner)

Why This Matters

PACT strictly forbids floating-point arithmetic for currency calculations (all monetary values are calculated in integer cents). Providing clear, copy-pasteable TypeScript code snippets in docs/DEVELOPMENT.md helps new contributors avoid common floating-point bugs.

Current Behavior

Section 7 in docs/DEVELOPMENT.md mentions that integer cents should be used for currency, but lacks a concise TypeScript example illustrating formatCentsToDollars, dollarsToCents, and sumCents.

Requested Change

Add a short fenced TypeScript code block under Section 7 in docs/DEVELOPMENT.md illustrating:

import { dollarsToCents, formatCentsToCurrency, sumCents } from '@/lib/money';

const stakeCents = dollarsToCents(25.50); // 2550
const totalCents = sumCents([stakeCents, 1000]); // 3550
const formatted = formatCentsToCurrency(totalCents); // "$35.50"

Acceptance Criteria

• TypeScript code example is added under Section 7 of docs/DEVELOPMENT.md.
• Snippet uses valid imported function names from src/lib/money.ts.
• Relative links and markdown formatting remain clean and valid.

Verification

node scratch/check-links.mjs

Contributor Notes

This is a markdown-only documentation task. No application logic changes are required.

Open Section 7 in docs/DEVELOPMENT.md and verify the exported function names in src/lib/money.ts before adding the requested fenced TypeScript example. Keep the change markdown-only, preserve valid links and formatting, and run node scratch/check-links.mjs; done means the snippet is present and the link check passes.