fix(filters): the year dialog fits a tablet, walks by arrow keys, names one year once

- a decade cell is a 36-high box with its count under the year (owner A)
- arrow keys walk the cells: along a decade, then to the nearest year below
- clearing the kept older year hands the focus on instead of dropping it
- More... shows while a year with titles is hidden, as a plain chip
- the decade caption is not read twice; the Plex range fields have names
- one Plex year is labelled 1999, not 1999-1999, via oneYear/singleYear
- tests for the Plex wiring and the feed year clearing the upload date

frontend/src/modules/plex/plexDetailAside.tsx

@@ -1,6 +1,6 @@
 import { useState, type ReactNode } from "react";
 import { useTranslation } from "react-i18next";
-import type { PlexFilters } from "../../lib/api";
+import { oneYear, type PlexFilters } from "../../lib/api";
 import { formatMoney, formatRuntime } from "../../lib/format";
 import type { AsideSection, DetailAsideState, DetailFacts } from "../../lib/plexDetail";
 import { regionName, vocab } from "../../lib/vocab";
@@ -75,7 +75,7 @@ function FactsSection({ facts, onFilter }: { facts: DetailFacts; onFilter?: OnFi
         <Filterable
           tag
           title={onFilter ? t("plex.info.filterYear", { year }) : undefined}
-          onClick={onFilter ? () => onFilter({ yearMin: year, yearMax: year }) : undefined}
+          onClick={onFilter ? () => onFilter(oneYear(year)) : undefined}
         >
           {year}
         </Filterable>