Count as queued only what a scan will download on its own (#113)

Every file in state 'pending' counted as waiting to download: 4420 in production, across 12
shows. Since #97 a scan only downloads among a feed's newest max_new_per_check items, so those
were back-catalogue episodes no scan would take; the real queue was 0.

A new state, 'held': listed and downloadable by hand, but outside the feed's newest items, or of
a feed nothing downloads automatically. Db::hold_back moves a feed's waiting files between
'pending' and 'held' each time the feed is due, changed or not, and again after its items are
stored, so a new episode, a raised limit or auto-download turned on or off moves them. A held
file keeps its item's place among the newest, as a downloaded one does. 'pending' now means
queued, so ipx status, /api/status and the dashboard read true without changing.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

CHANGELOG.md

@@ -26,6 +26,7 @@ and this project adheres to [Semantic Versioning](https://semver.org/spec/v2.0.0
 
 ### Fixed
 
+- The download queue, in `ipx status`, `/api/status` and the dashboard, counts only what iPX will download on its own: older episodes beyond a show's limit, and files of feeds that do not download automatically, are listed but no longer counted as waiting.
 - Artwork published on http is stored on https when its host serves it there, so the page loads it directly; the rest still comes through iPX.
 - An iPhone adding the site to its home screen finds the icon at the first address it tries.
 - A feed whose server hangs no longer holds up every scan: a feed gets 30 seconds, and connecting anywhere 10.