Discord (DXP4800 NAS, 7148 tracks): library updates kept dying with "Update appears stuck — no
progress for 300s (last phase: Fetching all tracks in bulk...)". not actually hung.
root cause: the bulk track/album fetch used a single 10000-item page, so a whole library came
back in ONE request that emitted NO progress while in flight. the watchdog (database_update_health)
kills a job with no progress for 300s — so on a slow server that one silent request tripped it even
though it was alive, not stuck. raising the timeout cap only buys the silent request more rope; a
bigger library or slower disk just needs a higher number. the per-batch progress line also only ran
when there was a NEXT page, so a sub-page-size library reported nothing at all.
fix: extract a pure paginate_all_items seam (core/library/bulk_paginate.py) that pages in 1000s and
reports progress after EVERY page — so the watchdog is fed on a cadence set by page size, not library
size, and can't starve mid-fetch no matter how big the library. both Jellyfin bulk loops (tracks +
albums, same defect) now route through it. preserves the failure-shrink resilience (halve to a floor,
then give up). does NOT change what's fetched — same query, fields, items.
note: changes nothing about WHICH tracks come back; only how they're paged + that every page reports.
keep the raised cap on dev as a margin — this is the actual fix. Plex/Navidrome don't share the
pattern (checked). 9 seam tests incl. the watchdog-feed invariant (progress count scales with
N/page_size, never one call for the whole library) + the sub-page regression + failure-shrink.
467 jellyfin/library tests green, ruff clean.
2fb142dded