Closes the Plex #9 backend backlog (frontend was the prior follow-up). Behavior-
neutral cleanup + two two-way-sync bug fixes; PW2 verified a non-bug.
fix(plex): watch-sync PW1 pagination + PW3 lost-update guard
- PW1 watch_history: the history is a GLOBAL cross-account feed read as a single
500-row page, then filtered to the owner — on a busy family server the owner's
recent views can sit past page 1 and be missed. Now paginate (desc) until the
since-cutoff, bounded by max_pages (daily reconcile is the backstop; logs if hit).
- PW3 push_state_to_plex: it flagged synced_to_plex=True unconditionally after a
push, so a local edit landing between the push and the flag-set was marked clean
and never pushed (lost update). Capture the row's freshest timestamp when the
push is scheduled (_push_watch) and only settle the flag if the row is unchanged.
- PW2 was flagged as "accountID hardcoded to 1" but is NOT a bug: on a PMS account 1
is reserved for the owner/admin and an owner link always holds the admin token —
added a clarifying comment so it isn't re-flagged.
chore(plex): backend dedup
- PC2 unified_library + facets shared a ~13-field filter Query signature + p-dict →
one LibraryFilters dataclass injected via Depends(); as_dict() feeds the builders.
- PS-C1 sync.py collection upsert dup (resync_collection ≈ _sync_collections) →
_upsert_collection().
- PS-C2 sync.py 8-field filterable-metadata block dup (_apply_item ≈ _sync_shows) →
_apply_facet_fields().
- PW-C1 _repush_dirty read duration from the mirrored PlexItem.duration_s instead of
a per-row plex.metadata() round-trip.
- PW-C2 rk→id map built inline in two places → _rk_to_id() helper.
28061353ec