Complete client UI i18n migration

Adds client-side i18n support, language settings, translated UI copy, and locale parity coverage.

packages/app/src/hooks/use-providers-snapshot.ts

@@ -1,5 +1,6 @@
 import { useCallback, useEffect, useMemo } from "react";
 import { useMutation, useQuery, useQueryClient, type QueryClient } from "@tanstack/react-query";
+import { useTranslation } from "react-i18next";
 import type { AgentProvider, ProviderSnapshotEntry } from "@getpaseo/protocol/agent-types";
 import type { DaemonClient } from "@getpaseo/client/internal/daemon-client";
 import { useHostRuntimeClient, useHostRuntimeIsConnected } from "@/runtime/host-runtime";
@@ -112,6 +113,7 @@ export function useProvidersSnapshot(
   serverId: string | null,
   options: UseProvidersSnapshotOptions = {},
 ): UseProvidersSnapshotResult {
+  const { t } = useTranslation();
   const queryClient = useQueryClient();
   const client = useHostRuntimeClient(serverId ?? "");
   const isConnected = useHostRuntimeIsConnected(serverId ?? "");
@@ -129,7 +131,7 @@ export function useProvidersSnapshot(
     staleTime: 60_000,
     queryFn: async () => {
       if (!client) {
-        throw new Error("Host is not connected");
+        throw new Error(t("workspace.terminal.hostDisconnected"));
       }
       return fetchProvidersSnapshot({ client, cwd });
     },