feat(phase-16): anonymous play & share telemetry substrate (wave 16.1)

Player-service play-session tracker (floor + 3-bucket classify), SharePopover share tracker with debounce, sendBeacon interop, proxied rate-limited POST api/event/{play,share}, append-only event logs + incremental play_counter with server-side release resolution. Migration authored, not applied. No anonId, no read surface.

DeepDrftPublic.Client/Controls/AudioPlayerProvider.razor.cs

@@ -10,6 +10,8 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
     [Inject] public required AudioInteropService AudioInterop { get; set; }
     [Inject] public required TrackMediaClient TrackMediaClient { get; set; }
     [Inject] public required ILogger<StreamingAudioPlayerService> Logger { get; set; }
+    [Inject] public required BeaconInterop Beacon { get; set; }
+    [Inject] public required IPlayEventSink PlayEventSink { get; set; }
 
     private IStreamingPlayerService? _audioPlayerService;
     private QueueService? _queueService;
@@ -23,7 +25,16 @@ public partial class AudioPlayerProvider : ComponentBase, IAsyncDisposable
         // EnsureInitializedAsync — that path is correct because audio contexts
         // require a user gesture anyway. Initializing eagerly here causes 4+
         // SignalR round-trips before any content is stable.
-        _audioPlayerService = new StreamingAudioPlayerService(AudioInterop, TrackMediaClient, Logger);
+        var player = new StreamingAudioPlayerService(AudioInterop, TrackMediaClient, Logger);
+
+        // Phase 16: bind the play-session tracker to the player after construction, the same way the
+        // queue binds — the player is built with `new`, not DI, so threading telemetry through its
+        // constructor would force the provider to over-resolve. The tracker owns the floor/bucket logic
+        // and emits via the injected sink (the beacon in production); the beacon also drives the
+        // page-unload close so a mid-play tab-close still records the listen. Attached on the concrete
+        // type before it is exposed through the IStreamingPlayerService field.
+        player.AttachTracker(new PlayTracker(PlayEventSink), Beacon);
+        _audioPlayerService = player;
 
         // Provider is the SOLE owner of OnStateChanged. When the service fires,
         // the provider re-renders, which cascades to its children automatically.