fix: avoid unbounded HTTP throttling and make buffer readout opt-in

Checks/system-playback.swift

@@ -22,8 +22,20 @@ struct SystemPlaybackChecks {
         let suite = "terebi.system-playback-check.\(UUID().uuidString)"
         let defaults = UserDefaults(suiteName: suite)!
         defer { defaults.removePersistentDomain(forName: suite) }
+        let initialModel = PlayerModel(defaults: defaults)
+        require(!initialModel.showsBufferInfo, "buffer readout defaults off before playback")
+        initialModel.setShowsBufferInfo(true)
+        require(initialModel.showsBufferInfo && initialModel.controlsVisible,
+                "buffer readout can be enabled before playback and reveals controls")
+        initialModel.shutdown()
+        let restoredModel = PlayerModel(defaults: defaults)
+        require(restoredModel.showsBufferInfo, "enabled buffer readout survives model recreation")
+        restoredModel.setShowsBufferInfo(false)
+        require(!restoredModel.showsBufferInfo, "buffer readout can be explicitly disabled")
+        restoredModel.shutdown()
         let model = PlayerModel(defaults: defaults)
         defer { model.shutdown() }
+        require(!model.showsBufferInfo, "explicitly disabled buffer readout survives model recreation")
         model.setVolume(0)
         let directory = URL(fileURLWithPath: CommandLine.arguments[1], isDirectory: true)
         let center = MPNowPlayingInfoCenter.default()
@@ -73,6 +85,11 @@ struct SystemPlaybackChecks {
         retainedSnapshot.buffered_end = min(retainedSnapshot.duration, retainedSnapshot.position + 1)
         model.applyState(retainedSnapshot)
         require(model.bufferedRange != nil, "loaded selection exposes retained media")
+        let retainedRange = model.bufferedRange
+        model.setShowsBufferInfo(true)
+        require(model.bufferedRange == retainedRange, "enabling buffer readout preserves retained media")
+        model.setShowsBufferInfo(false)
+        require(model.bufferedRange == retainedRange, "disabling buffer readout preserves retained media")
         model.closeFile()
         require(model.bufferedRange == nil, "accepted close immediately hides a stale retained-media snapshot")
         require(center.nowPlayingInfo == nil && center.playbackState == .stopped,