Problem

Fixes #4108 — removeCodeBlocks deletes entire code blocks (including their JSON payload) instead of extracting the content inside them.

The regex / ```[^]*``` /g` matches everything between the opening and closing fence markers and replaces all of it with an empty string. When Claude returns:

```json
{"facts": ["user likes TypeScript"]}

the function returns `""` and `JSON.parse` throws `SyntaxError: Unexpected end of JSON input`.

## Fix

Replace the regex with a capturing group that **extracts** the content inside code fences while stripping only the fence markers:

```ts
// Before (deletes content)
text.replace(/```[^`]*```/g, "")

// After (extracts content)
text.replace(/```(?:\w+)?\n?([\s\S]*?)```/g, "$1").trim()

Tests

Added remove-code-blocks.test.ts covering:

• JSON in ```json fence
• Bare ``` fence
• Plain text passthrough (no fences)
• Multiple code blocks
• Claude-style response with surrounding text