chore: bump major versions for low/medium-risk dependencies

Update 27 packages to their latest major versions:

Tier 3 (low risk): @fontsource/roboto (5.x), @fontsource/roboto-mono (5.x),
@fortawesome/* (7.x), cross-env (10.x), debounce (3.x), uuid (13.x),
@vitejs/plugin-react-swc (4.x), concurrently (9.x), css-loader (7.x),
cypress (15.x), style-loader (4.x), vite (7.x), vite-plugin-node-polyfills
(0.25.x), vite-plugin-static-copy (3.x), wait-on (9.x)

Tier 2 (medium risk): express (5.x), i18next (25.x), i18next-http-backend
(3.x), react-i18next (16.x), marked (17.x), react-markdown (10.x),
remark-gfm (4.x), remark-math (6.x), rehype-katex (7.x)

Code changes required by the upgrades:
- debounce v3: switch to default import
- react-markdown v10: wrap in div for className (removed prop)
- express v5: use named wildcard params (*path) and array join
- Remove @types/debounce (v3 ships own types)

All 24 E2E tests pass.

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

Author: jessealama

client/src/components/markdown.tsx

@@ -26,6 +26,8 @@ export function Markdown(props: any) {
     rehypePlugins: [...props.remarkPlugins ?? [], rehypeKatex],
   };
   return (
-    <ReactMarkdown {...newProps} className="markdown" />
+    <div className="markdown">
+      <ReactMarkdown {...newProps} />
+    </div>
   );
 }

client/src/state/store.ts

@@ -2,7 +2,7 @@
  * @fileOverview configure the store and save the state periodically to the browser storage
 */
 import { configureStore } from '@reduxjs/toolkit';
-import { debounce } from "debounce";
+import debounce from "debounce";
 
 import { connection } from '../connection'
 import { apiSlice } from './api'