fix: update comments in latex utility and refactor variable declaration for clarity

frontend/eslint.config.js

@@ -1,14 +1,14 @@
-import js from '@eslint/js'
-import globals from 'globals'
-import reactHooks from 'eslint-plugin-react-hooks'
-import reactRefresh from 'eslint-plugin-react-refresh'
-import tseslint from 'typescript-eslint'
-import { defineConfig, globalIgnores } from 'eslint/config'
+import js from "@eslint/js";
+import globals from "globals";
+import reactHooks from "eslint-plugin-react-hooks";
+import reactRefresh from "eslint-plugin-react-refresh";
+import tseslint from "typescript-eslint";
+import { defineConfig, globalIgnores } from "eslint/config";
 
 export default defineConfig([
-  globalIgnores(['dist']),
+  globalIgnores(["dist"]),
   {
-    files: ['**/*.{ts,tsx}'],
+    files: ["**/*.{ts,tsx}"],
     extends: [
       js.configs.recommended,
       tseslint.configs.recommended,
@@ -19,5 +19,18 @@ export default defineConfig([
       ecmaVersion: 2020,
       globals: globals.browser,
     },
+    rules: {
+      "react-hooks/rules-of-hooks": "warn",
+      "react-hooks/exhaustive-deps": "warn",
+      "react-hooks/set-state-in-effect": "warn",
+      "react-hooks/purity": "warn",
+      "react-refresh/only-export-components": "warn",
+      "no-control-regex": "off",
+      "@typescript-eslint/no-unused-vars": [
+        "warn",
+        { argsIgnorePattern: "^_" },
+      ],
+      "prefer-const": "warn",
+    },
   },
-])
+]);

frontend/src/utils/latex.ts

@@ -47,9 +47,9 @@ export const highlightCode = (code: string, _lang: string): string => {
 
   // Extract comments and strings into placeholders before applying keyword/number/fn regexes
   // so later passes don't corrupt previously-injected span tag attributes.
-  //  is a Unicode private-use-area char that never appears in source code.
+  // \uE000 is a Unicode private-use-area char that never appears in source code.
   // Word chars around the index (e.g. _HL0_) prevent \b(\d+)\b from matching the index digits.
-  let result = escaped
+  const result = escaped
     .replaceAll(/(\/\/[^\n]*|#[^\n]*)/g, (m) => {
       const i = spans.length
       spans.push(`<span class="cm-comment">${m}</span>`)