fix(plex): the slow line says both rates in one unit

Each rate took its own unit, so a link under a megabit read "needs 1.4
Mbps, 800 kbps arrives". `fmtBitrates` picks the unit the largest takes
for all of them. The away-window header now says what ends an absence
outside hls.js (the answer) and after the error (the viewer's retry).

frontend/src/lib/plexStats.ts

@@ -64,6 +64,16 @@ export function fmtBitrate(bps: number | undefined, lang: string): string {
   return `${formatNumber(Math.round(bps / 1000), lang)} kbps`;
 }
 
+// Rates read side by side ("needs 1.4 Mbps, 0.8 Mbps arrives"): one unit for all of them, the one
+// the largest would take alone, so they compare at a glance — never "1.4 Mbps" beside "800 kbps".
+export function fmtBitrates(rates: number[], lang: string): string[] {
+  const largest = Math.max(0, ...rates);
+  if (largest < 1_000_000) return rates.map((bps) => fmtBitrate(bps, lang));
+  return rates.map((bps) =>
+    bps > 0 ? `${formatDecimal(bps / 1_000_000, lang)} Mbps` : fmtBitrate(bps, lang),
+  );
+}
+
 // Seconds of buffer ahead of the playhead → "12.3 sec" / "12,3 mp".
 export function fmtBufferSecs(s: number, lang: string): string {
   if (!Number.isFinite(s) || s < 0) return DASH;