fix(lint): resolve eslint warnings, type errors and clean unused code

proxy.ts

@@ -2,7 +2,7 @@ import { NextResponse } from 'next/server';
 import type { NextRequest } from 'next/server';
 import { i18n } from './app/dictionaries';
 
-function getLocale(request: NextRequest): string {
+function getLocale(): string {
   // Always return default locale for now (can be improved to read headers)
   return i18n.defaultLocale;
 }
@@ -26,7 +26,7 @@ export function proxy(request: NextRequest) {
   );
 
   if (pathnameIsMissingLocale) {
-    const locale = getLocale(request);
+    const locale = getLocale();
     return NextResponse.redirect(
       new URL(`/${locale}${pathname === '/' ? '' : pathname}`, request.url)
     );