## Why
LaTeX content commonly uses `\(...\)` and `\[...\]`, but CodeNomad only
recognizes `$...$` and `$$...$$` through `marked-katex-extension`.
## What
- Add parser-native Marked rules for inline `\(...\)` and display
`\[...\]` formulas.
- Preserve existing dollar math, code spans and fences, escaped
delimiters, and unmatched text.
- Add focused regression tests and document the delimiter design.
