refactor(channels): collapse the stats row into a Stats hover chip (R13 S3)

The six inline catalog stats crammed into the tab row become one compact
"Stats" chip that reveals the numbers on hover — a new ChannelStatsPopover on
the AnchoredPopover hover mode, one icon-per-row (channels, recent synced, full
history, [ETA], my videos, quota left). Kept in the manager's own toolbar (the
header SyncStatus is global; these are channel-catalog figures). Retires the
local Stat helper + the now-unused formatEta import. i18n channels.stats.label
(HU+EN). Self-E2E'd: hover reveals the list. gate green (tsc/eslint-0/prettier).

frontend/src/components/Channels.tsx

@@ -7,7 +7,6 @@ import ExcludedChannelList from "./ExcludedChannelList";
 import { api, type ManagedChannel } from "../lib/api";
 import { notifyYouTubeActionError } from "../lib/youtubeErrors";
 import { accountKey, LS } from "../lib/storage";
-import { formatEta } from "../lib/format";
 import { buildChannelColumns } from "./channelColumns";
 import { notify } from "../lib/notifications";
 import Tooltip from "./Tooltip";
@@ -21,6 +20,7 @@ import ViewSwitcher, { type ViewOption } from "./ViewSwitcher";
 import ColumnSortControl from "./ColumnSortControl";
 import FilterChipGroup, { filterChipClass } from "./FilterChipGroup";
 import ActionMenu, { type ActionMenuItem } from "./ActionMenu";
+import ChannelStatsPopover from "./ChannelStatsPopover";
 import Pager from "./Pager";
 import { CHANNEL_LAYOUTS, type ChannelLayout } from "../lib/channelLayout";
 import { sortRows } from "../lib/columnSort";
@@ -305,48 +305,9 @@ export default function Channels() {
     />
   );
 
-  // The catalog-wide stats ride on the right of the tab row (subscribed only), leaving room for
-  // future tabs on the left.
-  const statsBlock = (
-    <div className="flex flex-wrap items-center justify-end gap-x-5 gap-y-1 text-sm text-muted">
-      {s && (
-        <>
-          <Stat
-            label={t("channels.stats.channels")}
-            value={s.channels_total}
-            hint={t("channels.stats.channelsHint")}
-          />
-          <Stat
-            label={t("channels.stats.recentSynced")}
-            value={`${s.channels_recent_synced}/${s.channels_total}`}
-            hint={t("channels.stats.recentSyncedHint")}
-          />
-          <Stat
-            label={t("channels.stats.fullHistory")}
-            value={`${s.channels_deep_done}/${s.channels_deep_requested}`}
-            hint={t("channels.stats.fullHistoryHint")}
-          />
-          {s.deep_pending_count > 0 && (
-            <Stat
-              label={t("channels.stats.left")}
-              value={formatEta(s.deep_eta_seconds)}
-              hint={t("channels.stats.leftHint", { count: s.deep_pending_count })}
-            />
-          )}
-          <Stat
-            label={t("channels.stats.myVideos")}
-            value={s.my_videos.toLocaleString()}
-            hint={t("channels.stats.myVideosHint")}
-          />
-          <Stat
-            label={t("channels.stats.quotaLeft")}
-            value={s.quota_remaining_today.toLocaleString()}
-            hint={t("channels.stats.quotaLeftHint")}
-          />
-        </>
-      )}
-    </div>
-  );
+  // The catalog-wide stats collapse into a compact "Stats" hover chip (right of the tab row, subscribed
+  // only) instead of a crowded inline row.
+  const statsBlock = s ? <ChannelStatsPopover status={s} /> : null;
 
   // Catalog-wide, occasional actions — tucked into a shared ⋯ overflow menu so they stop crowding the
   // tags row. Pending mutations keep the item visible but disabled, with a spinning icon.
@@ -596,13 +557,3 @@ export default function Channels() {
     </>
   );
 }
-
-function Stat({ label, value, hint }: { label: string; value: string | number; hint?: string }) {
-  return (
-    <Tooltip hint={hint ?? ""}>
-      <span className={hint ? "cursor-help" : ""}>
-        <span className="text-fg font-semibold">{value}</span> {label}
-      </span>
-    </Tooltip>
-  );
-}