Phase 1: Infrastructure setup - Install next-intl and create basic i18n structure

- Install next-intl package
- Create LanguageProvider hook with localStorage persistence
- Create IntlProvider component for next-intl integration
- Create Providers wrapper component
- Update layout.tsx to include providers and set default lang to 'es'
- Create initial translation files (common.json) for es, en, ca
- Fix pre-existing TypeScript errors in various pages

All tests passing, build successful.

frontend/app/admin/trades/page.tsx

@@ -5,6 +5,7 @@ import { Permission } from "../../auth-context";
 import { adminApi } from "../../api";
 import { Header } from "../../components/Header";
 import { SatsDisplay } from "../../components/SatsDisplay";
+import { StatusBadge } from "../../components/StatusBadge";
 import { EmptyState } from "../../components/EmptyState";
 import { ConfirmationButton } from "../../components/ConfirmationButton";
 import { useRequireAuth } from "../../hooks/useRequireAuth";
@@ -275,7 +276,9 @@ export default function AdminTradesPage() {
                         </span>
                       </div>
 
-                      <StatusBadge tradeStatus={trade.status} style={{ marginTop: "0.5rem" }} />
+                      <StatusBadge tradeStatus={trade.status} style={{ marginTop: "0.5rem" }}>
+                        {""}
+                      </StatusBadge>
                     </div>
 
                     {/* Actions */}