feat(webui): improve LaTeX rendering with currency detection (#16508)

* webui : Revised LaTeX formula recognition

* webui : Further examples containg amounts

* webui : vitest for maskInlineLaTeX

* webui: Moved preprocessLaTeX to lib/utils

* webui: LaTeX in table-cells

* chore: update webui build output (use theirs)

* webui: backslash in LaTeX-preprocessing

* chore: update webui build output

* webui: look-behind backslash-check

* chore: update webui build output

* Apply suggestions from code review

Code maintenance (variable names, code formatting, string handling)

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

* webui: Moved constants to lib/constants.

* webui: package woff2 inside base64 data

* webui: LaTeX-line-break in display formula

* chore: update webui build output

* webui: Bugfix (font embedding)

* webui: Bugfix (font embedding)

* webui: vite embeds assets

* webui: don't suppress 404 (fonts)

* refactor: KaTeX integration with SCSS

Moves KaTeX styling to SCSS for better customization and font embedding.

This change includes:
- Adding `sass` as a dev dependency.
- Introducing a custom SCSS file to override KaTeX variables and disable TTF/WOFF fonts, relying solely on WOFF2 for embedding.
- Adjusting the Vite configuration to resolve `katex-fonts` alias and inject SCSS variables.

* fix: LaTeX processing within blockquotes

* webui: update webui build output

---------

Co-authored-by: Aleksander Grygier <aleksander.grygier@gmail.com>

tools/server/webui/src/lib/constants/latex-protection.ts

@@ -0,0 +1,35 @@
+/**
+ * Matches common Markdown code blocks to exclude them from further processing (e.g. LaTeX).
+ * - Fenced: ```...```
+ * - Inline: `...` (does NOT support nested backticks or multi-backtick syntax)
+ *
+ * Note: This pattern does not handle advanced cases like:
+ *       `` `code with `backticks` `` or \\``...\\``
+ */
+export const CODE_BLOCK_REGEXP = /(```[\s\S]*?```|`[^`\n]+`)/g;
+
+/**
+ * Matches LaTeX math delimiters \(...\) and \[...\] only when not preceded by a backslash (i.e., not escaped),
+ * while also capturing code blocks (```, `...`) so they can be skipped during processing.
+ *
+ * Uses negative lookbehind `(?<!\\)` to avoid matching \\( or \\[.
+ * Using the look‑behind pattern `(?<!\\)` we skip matches
+ * that are preceded by a backslash, e.g.
+ * `Definitions\\(also called macros)` (title of chapter 20 in The TeXbook)
+ * or `\\[4pt]` (LaTeX line-break).
+ *
+ * group 1: code-block
+ * group 2: square-bracket
+ * group 3: round-bracket
+ */
+export const LATEX_MATH_AND_CODE_PATTERN =
+	/(```[\S\s]*?```|`.*?`)|(?<!\\)\\\[([\S\s]*?[^\\])\\]|(?<!\\)\\\((.*?)\\\)/g;
+
+/** Regex to capture the content of a $$...\\\\...$$ block (display-formula with line-break) */
+export const LATEX_LINEBREAK_REGEXP = /\$\$([\s\S]*?\\\\[\s\S]*?)\$\$/;
+
+/** map from mchem-regexp to replacement */
+export const MHCHEM_PATTERN_MAP: readonly [RegExp, string][] = [
+	[/(\s)\$\\ce{/g, '$1$\\\\ce{'],
+	[/(\s)\$\\pu{/g, '$1$\\\\pu{']
+] as const;