a37dad33c7
New composables/useAsyncAction.js owns the loading/error/try-finally lifecycle. Migrated 11 stores: credentials, downloads, sources, posts (error=raw) + ml, artistDirectory, tagDirectory, showcase, suggestions, seriesReader, modal (error=message). The errorAs option preserves each store's existing error shape so store.error keeps the same type for components (~50 consumption sites unchanged). Stores whose catch also reset data (suggestions/seriesReader/modal) clear it upfront instead. Deliberately NOT migrated (special control flow, would change behavior): artist (conditional 404 catch + dual loading states), migration (rethrows), gallery (inflight-id stale-response guard), and the Shape-B no-catch / loaded-guard / keyed-cache stores. Net -77 lines. Co-Authored-By: Claude Opus 4.7 (1M context) <noreply@anthropic.com>