chore: upgrade i18next 26, prettier 3, fontsource-variable, domhandler 6, lint-staged 17

- i18next 23->26 + react-i18next 15->17
- prettier 2->3, reformat all files
- replace @fontsource/inter with @fontsource-variable/inter 5, update import path
- domhandler 5->6 (aligns with transitive deps)
- lint-staged 16->17

src/index.css

@@ -1,6 +1,7 @@
 @font-face {
   font-family: Twemoji;
-  src: url('../public/font/Twemoji.Mozilla.v15.1.0.woff2'),
+  src:
+    url('../public/font/Twemoji.Mozilla.v15.1.0.woff2'),
     url('../public/font/Twemoji.Mozilla.v15.1.0.ttf');
   font-display: swap;
 }