Function needsUnicodeEncoding

needsUnicodeEncoding(str: string): boolean
Checks if a string contains characters that require UTF-16BE encoding.

PDFDocEncoding can represent:
- ASCII characters (0-127)
- Special PDF characters (mapped from specific Unicode chars to bytes 128-159)
- ISO Latin-1 characters (160-255)
Anything outside this range requires UTF-16BE encoding.
Parameters
- str: string
  The string to check
Returns boolean
True if the string contains characters that cannot be represented in PDFDocEncoding
Example
```
needsUnicodeEncoding('Hello') // Returns false (ASCII)
needsUnicodeEncoding('Café') // Returns false (ISO Latin-1)
needsUnicodeEncoding('Test • item') // Returns false (special PDF char)
needsUnicodeEncoding('Hello 世界') // Returns true (needs UTF-16BE)
```
- Defined in packages/pdf-lite/src/utils/needsUnicodeEncoding.ts:24