feat: store video bandwidth estimate

src/components/embeds/players/video-player.tsx

···
 
 	const [playing, setPlaying] = createSignal(false);
 
+	const bwEstimate = currentAccount?.preferences.ui.videoBwEstimate;
 	const hls = new Hls({
 		capLevelToPlayerSize: true,
-		startLevel: 1,
+
+		// the '-1' value makes a test request to estimate bandwidth and quality level
+		// before showing the first fragment
+		startLevel: bwEstimate === undefined ? -1 : Hls.DefaultConfig.startLevel,
+
 		xhrSetup(xhr, urlString) {
 			// We want to replace the URL here so it points directly to the CDN,
 			// and not the middleware service.
···
 		},
 	});
 
+	if (bwEstimate !== undefined) {
+		hls.bandwidthEstimate = bwEstimate;
+	}
+
 	onCleanup(() => hls.destroy());
 
 	hls.loadSource(embed.playlist);
···
 					if (!isMobile && currentAccount) {
 						node.volume = currentAccount.preferences.ui.mediaVolume;
 					}
+
+					hls.on(Hls.Events.FRAG_LOADED, () => {
+						if (currentAccount) {
+							currentAccount.preferences.ui.videoBwEstimate = hls.bandwidthEstimate;
+						}
+					});
 
 					hls.on(Hls.Events.LEVEL_LOADED, (_event, data) => {
 						const hasAudio = data.levelInfo.audioCodec !== undefined;

src/lib/preferences/account.ts

···
 }
 
 export interface UIPreferences {
+	/** Media bandwidth estimate */
+	videoBwEstimate: number | undefined;
 	/** Media player volume */
 	mediaVolume: number;
 }

src/lib/states/session.tsx

···
 					},
 				],
 				ui: {
+					videoBwEstimate: undefined,
 					mediaVolume: 0.25,
 				},
 				composer: {