Function formatNumber

formatNumber(value: number, decimalPlaces?: number): string
Format a number with thousands separators and optional decimal places

Provides locale-aware number formatting with thousands separators and configurable decimal precision.
Parameters
- value: number
  Number to format
- OptionaldecimalPlaces: number
  Optional number of decimal places to display
Returns string
Formatted number string with separators
Example
```
formatNumber(1234567)          // "1,234,567"
formatNumber(1234.5678)        // "1,234.568" (locale dependent)
formatNumber(1234.5678, 2)     // "1234.57"
formatNumber(999.999, 1)       // "1000.0"
```
- Defined in utils/formatUtils.ts:222