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.

DeepDrftPublic.Client/Controls/SharePopover.razor.cs

@@ -1,5 +1,6 @@
 using DeepDrftModels.Enums;
 using DeepDrftPublic.Client.Common;
+using DeepDrftPublic.Client.Services;
 using Microsoft.AspNetCore.Components;
 using Microsoft.JSInterop;
 
@@ -27,6 +28,7 @@ public partial class SharePopover : ComponentBase, IDisposable
 
     [Inject] public required NavigationManager Navigation { get; set; }
     [Inject] public required IJSRuntime JS { get; set; }
+    [Inject] public required ShareTracker ShareTracker { get; set; }
 
     private bool IsReleaseMode => ReleaseEntryKey is not null;
 
@@ -67,6 +69,14 @@ public partial class SharePopover : ComponentBase, IDisposable
     {
         if (await CopyToClipboard(LinkUrl))
         {
+            // Record a share only after the clipboard write succeeds (§1b). Release mode targets the
+            // release EntryKey; track mode targets the track EntryKey. The tracker debounces repeat
+            // copies of the same (target, channel) into one event.
+            if (IsReleaseMode)
+                ShareTracker.RecordShare(ShareTargetType.Release, ReleaseEntryKey!, ShareChannel.Link);
+            else if (!string.IsNullOrWhiteSpace(EntryKey))
+                ShareTracker.RecordShare(ShareTargetType.Track, EntryKey, ShareChannel.Link);
+
             _linkCopied = true;
             await ResetAfterDelay(() => _linkCopied = false);
         }
@@ -76,6 +86,11 @@ public partial class SharePopover : ComponentBase, IDisposable
     {
         if (await CopyToClipboard(EmbedSnippet))
         {
+            // Embed is a single-track affordance only (release mode hides it), so this always targets a
+            // track with channel = embed.
+            if (!string.IsNullOrWhiteSpace(EntryKey))
+                ShareTracker.RecordShare(ShareTargetType.Track, EntryKey, ShareChannel.Embed);
+
             _embedCopied = true;
             await ResetAfterDelay(() => _embedCopied = false);
         }