Write a replaceement for `remark-math` to only handle the \( ... \) formulas

Markdown will interpret `$100 to $200` as a formula with the default syntax:


At the moment the `\( ... \)` formulas are just converted to `$ ... $` with a regex:
```
let convertedMsg = msg.text
.replace(/\\\((.*?)\\\)/g, '$$ $1 $$')
.replace(/\\\[\n([\s\S]*?)\n(\s*)\\\]/g, '$$$$\n$1\n$2$$$$'); // Preserve leading whitespace before closing $$
```

- Write a remark plugin to handle only the bracket formulas
- Add an option to select md formula syntax per-agent.

Start by locating the message-processing code containing the shown regex and inspect how per-agent options are represented. Done means a remark plugin handles only the \( ... \) and \[ ... \] formulas without treating currency such as $100 to $200 as math, with a per-agent choice of formula syntax.

Written by the indexing model from the issue text.