Three targeted frontend fixes:
1. pdf.js smart preload (thumbnail.js, resourceIcon.js). The first PDF
thumbnail of a session stalled 1-2s on the lazy import of the ~1.3 MB
pdf.js stack. buildResourceIcon() now fires thumbnail.preloadPdf()
the moment a PDF row enters the DOM, warming both the module
(~300 KB, via the now promise-memoized getPdfjsLib, shared with real
users) and the worker script (~1 MB, via a cache-priming fetch —
pdf.js only requests it on first getDocument). Only folders that
actually contain PDFs pay the download; idempotent after first call,
resets on failure so transient offline retries.
2. Admin migration poll cleanup (admin.js). The 2s setInterval kept
hitting the API and updating hidden DOM after leaving the Storage
tab, and polled a failing endpoint forever after session expiry
(!resp.ok returned without clearing). New stopMigrationPolling()
helper, invoked on tab switch away from Storage, on non-running
status, and on failed polls; tab re-entry re-arms via loadStorage().
3. resourceList.js render hoisting. Per-row i18n.t() type-cell lookups
and the fully item-invariant _renderCustomActions() HTML were
recomputed for every row; they now resolve once per batch via
_buildItemLabels() (per-category labels memoized, rebuilt each
batch so locale switches keep working). _findLaneByKey() swaps the
container-wide attribute querySelector for an O(1) _lanes Map kept
in sync at the only lane create/wipe sites.
https://claude.ai/code/session_0193Hff42gaA962wThxMGSd1
Claude
ecbdaee19e