Feature/svelte latex regex (#16136)

[srogmann]

Close #16136

This PR handles LaTeX blocks in (...) and [...], as well as dollar amounts like $100 that should not be interpreted as inline LaTeX.

Examples (e.g. prompt "Think of a grade 4 math question regarding amounts."):

• ( \mathrm{GL}_2(\mathbb{F}_7) ): Group of invertible matrices with entries in (\mathbb{F}_7).
• Some kernel of (\mathrm{SL}_2(\mathbb{F}_7)):
  [
  \left{ \begin{pmatrix} 1 & 0 \ 0 & 1 \end{pmatrix}, \begin{pmatrix} -1 & 0 \ 0 & -1 \end{pmatrix} \right} = {\pm I}
  ]
• $100 and $12.99 are amounts, not LaTeX.
• I have $10, $3.99 and $x + y$ and $100x$. The amount is $2,000.

@allozaur : I wrote most of this PR a week ago, only just now noticed issue #16136 and your PR #16496. In math-formulas.ts, I've added examples for Storybook, along with tests for Vitest. Feel free to take a look and let me know your thoughts. Detecting inline LaTeX is inherently tricky, so my approach likely won't cover every edge case, but I hope it's a step in the right direction.

[allozaur]

Hey @srogmann! Thank you for this contribution :) Yeah, we will definitely work sth out from these PRs :)

[allozaur]

@ggerganov could u also please take a look at this and test your edge cases?

@watamario15 @squik67 also some feedback & testing from you would be really useful :)

[ggerganov]

These are still not rendered (using gpt-oss):

[allozaur]

Okay, thanks for reporting @ggerganov. I'd like to wait just a bit longer for @watamario15 and @squik67 to add their feedback and verify if there are more edge cases to be addressed before we introduce any further improvements to this.

[srogmann]

Thanks for the tests! I can reproduce the non-rendered formulas. The \[-marker is not at line-begin in the non-working cases.

Example: working and non-working.

- Algebra:
\[
x = \frac{-b \pm \sqrt{\,b^{2}-4ac\,}}{2a}
\]
- Algebra: \[
x = \frac{-b \pm \sqrt{\,b^{2}-4ac\,}}{2a}
\]

I'll have a look at it.

[watamario15]

From my quick check, this doesn't get rendered:

- 1 kg の質量は  
  \[
  E = (1\ \text{kg}) \times (3.0 \times 10^8\ \text{m/s})^2 \approx 9.0 \times 10^{16}\ \text{J}
  \]  
  というエネルギーに相当します。これは約 21 百万トンの TNT が爆発したときのエネルギーに匹敵します。