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/app/plugins/markdown/internal/utils.ts

@@ -53,7 +53,7 @@ export const replaceMatch = <C>(
   text: string,
   match: MatchResult,
   content: C,
-  processPart: (txt: string) => Array<string | C>
+  processPart: (txt: string) => Array<string | C>,
 ): Array<string | C> => [
   ...processPart(beforeMatch(text, match)),
   content,