Improve stream quality: stop capping resolution, allow AVPlayer to ramp

SingleStream: pass preserveServerResolutionWhenBest=false so "best"
always reaches the server for a full multi-variant manifest. Increase
buffer to 8s and enable automaticallyWaitsToMinimizeStalling so AVPlayer
can measure bandwidth and select higher variants. Add quality monitor
that nudges AVPlayer if observed bandwidth far exceeds indicated bitrate.

MultiStream: remove broken URL-param resolution detection that falsely
skipped upgrades, log actual indicatedBitrate instead. Extend upgrade
check windows from [2,4,7]s to [2,4,7,15,30]s for slow-to-stabilize
streams.

Co-Authored-By: Claude Opus 4.6 (1M context) <noreply@anthropic.com>

mlbTVOS/Views/DashboardView.swift

@@ -260,7 +260,11 @@ struct DashboardView: View {
             mediaId: selection.broadcast.mediaId,
             streamURLString: selection.broadcast.streamURL
         )
-        guard let url = await viewModel.resolveStreamURL(for: stream) else { return nil }
+        guard let url = await viewModel.resolveStreamURL(
+            for: stream,
+            resolutionOverride: viewModel.defaultResolution,
+            preserveServerResolutionWhenBest: false
+        ) else { return nil }
         return SingleStreamPlaybackSource(url: url)
     }