feat(logs): add inline JSON syntax highlighting for log attributes (#111730)

Add inline syntax highlighting for JSON embedded within log attribute
values in the expanded attribute tree view.

Previously (LOGS-400), only attribute values that were *entirely* valid
JSON got pretty-printed with `StructuredEventData`. Values like `This is
my JSON: {"it": "would be", "nice": ["to", "highlight"], "this": true}`
rendered as plain text. Now, the JSON portion gets Prism-based syntax
colorizing inline — keys, strings, numbers, booleans, and punctuation
each get their own color — without adding newlines or changing the
layout.

<img width="838" height="245" alt="Screenshot of a log with a myData
field showing syntax-highlighted JSON object"
src="https://github.com/user-attachments/assets/7b78bb01-5be9-494e-9010-2008fde3b59c"
/>

The JSON extraction logic lives in a standalone utility
(`extractJsonFromText`) that uses string-aware bracket matching to
correctly handle braces inside quoted strings and escape sequences —
unlike existing npm packages (`balanced-match`,
`extract-json-from-string`) which break on these cases. I intentionally
set this up so that it acts like a standalone importable utility. It'd
be nifty if we could publish this as its own package...

Fixes LOGS-636

Made with [Cursor](https://cursor.com)

Co-authored-by: Claude Sonnet 4 <noreply@anthropic.com>

Author: 2 people