v3: error cards across the app, friendly network errors, code quality pass

src/pages/UserPlaylists.tsx

@@ -8,6 +8,7 @@ import {
 import { Link, useParams } from "react-router";
 
 import { API_URL } from "../config/api.ts";
+import { friendlyFetchError } from "../utils/apiError.ts";
 import type {
   PaginatedData,
   Playlist,
@@ -105,7 +106,7 @@ export function UserPlaylists() {
         .catch((err) =>
           setState({
             status: "error",
-            error: err instanceof Error ? err.message : "Failed to load",
+            error: friendlyFetchError(err),
           })
         );
       return;
@@ -148,7 +149,7 @@ export function UserPlaylists() {
       .catch((err) =>
         setState({
           status: "error",
-          error: err instanceof Error ? err.message : "Failed to load",
+          error: friendlyFetchError(err),
         })
       );
   }, [username]);