Localize Date and Currency Formatting in UI

[Fatimasanusi]

Asset prices and timestamps are currently hardcoded to USD ($) and US date formats (MM/DD/YYYY). We need to respect the user's browser locale for proper internationalization.

Acceptance Criteria:

• Replace hardcoded currency symbols with Intl.NumberFormat for fiat equivalencies.
• Use Intl.DateTimeFormat (or date-fns) to format order execution timestamps based on the user's locale.
• Ensure formatting handles fallback gracefully if the locale is unrecognized.