Function CleanJSON

CleanJSON(inputString: string | null): string | null
Cleans and extracts valid JSON from various input formats including double-escaped strings, strings with embedded JSON, and markdown code blocks.

This function handles multiple scenarios in the following priority order:
1. Valid JSON: If the input is already valid JSON, it returns it formatted
2. Double-escaped JSON: Handles strings with escaped quotes (\") and newlines (\n)
3. Markdown blocks: Extracts JSON from ```json code blocks (only as last resort)
4. Mixed content: Extracts JSON objects/arrays from strings with surrounding text
Parameters
- inputString: string | null
  The string to process, which may contain JSON in various formats
Returns string | null
A formatted JSON string if valid JSON is found, otherwise null
Example
```
// Simple JSON
CleanJSON('{"name": "test"}') 
// Returns: '{\n  "name": "test"\n}'
```
Example
```
// Double-escaped JSON
CleanJSON('{\\"name\\": \\"test\\", \\"value\\": 123}')
// Returns: '{\n  "name": "test",\n  "value": 123\n}'
```
Example
// JSON with embedded markdown (preserves the markdown in string values) CleanJSON('{"text": "json\\n{\\"inner\\": true}\\n"}') // Returns: '{\n "text": "json\\n{\\"inner\\": true}\\n"\n}'

Example
// Markdown block extraction (only when not valid JSON) CleanJSON('Some text json\n{"extracted": true}\n more text') // Returns: '{\n "extracted": true\n}'
- Defined in util.ts:261