fix: let AbortError propagate through the API client

The network-error wrapping added in the error-boundary work also caught
deliberate AbortController cancellations and turned them into a network_error
ApiError, breaking callers that distinguish "cancelled" from "failed" (the
cancellable admin fetches). Rethrow DOMException AbortError unchanged; only
genuine network failures become ApiError(status 0).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>

frontend/package.json

@@ -1,6 +1,6 @@
 {
   "name": "mangalord-frontend",
-  "version": "0.128.2",
+  "version": "0.128.3",
   "private": true,
   "type": "module",
   "scripts": {