fix(telemetry): first-party fetch for play/share, beacon only on unload

Route normal play closes (end/switch/stop) and all shares through a same-origin
HttpClient POST so privacy-hardened browsers stop blocking them; keep sendBeacon
for the tab-unload edge. Rename the JS module off telemetry/beacon to session/
lifecycle so the retained fallback isn't name-matched. No new data or identifiers.

DeepDrftTests/ShareTrackerTests.cs

@@ -1,33 +1,27 @@
 using DeepDrftModels.Enums;
 using DeepDrftPublic.Client.Services;
 using Microsoft.AspNetCore.Components;
-using Microsoft.JSInterop;
-using Microsoft.JSInterop.Infrastructure;
 
 namespace DeepDrftTests;
 
 /// <summary>
 /// Unit tests for the Phase 16 share tracker (<see cref="ShareTracker"/>): the per-(target,channel)
 /// debounce (§1b — at most one event per target+channel per 60s window per session). The tracker fires
-/// through a beacon that wraps <see cref="IJSRuntime"/>; the tests use a no-op JS runtime (the send is
+/// through the first-party <see cref="IEventPoster"/>; the tests use a no-op poster (the POST is
 /// fire-and-forget and its outcome is irrelevant) and assert on the debounce decision via the bool the
 /// recorder returns — true when an event fired, false when debounced.
 /// </summary>
 [TestFixture]
 public class ShareTrackerTests
 {
-    // sendBeacon interop is fire-and-forget; the tracker never reads the result, so a no-op runtime that
-    // returns default for any invocation is sufficient to exercise the debounce logic.
-    private sealed class NoopJsRuntime : IJSRuntime
+    // The first-party POST is fire-and-forget; the tracker never reads the result, so a no-op poster that
+    // completes immediately is sufficient to exercise the debounce logic.
+    private sealed class NoopEventPoster : IEventPoster
     {
-        public ValueTask<TValue> InvokeAsync<TValue>(string identifier, object?[]? args)
-            => ValueTask.FromResult<TValue>(default!);
-
-        public ValueTask<TValue> InvokeAsync<TValue>(string identifier, CancellationToken cancellationToken, object?[]? args)
-            => ValueTask.FromResult<TValue>(default!);
+        public Task PostAsync(string url, string json) => Task.CompletedTask;
     }
 
-    // Minimal NavigationManager so the tracker can compose the (unused-in-test) beacon URL.
+    // Minimal NavigationManager so the tracker can compose the (unused-in-test) event URL.
     private sealed class TestNavigationManager : NavigationManager
     {
         public TestNavigationManager() => Initialize("https://deepdrft.test/", "https://deepdrft.test/");
@@ -49,7 +43,7 @@ public class ShareTrackerTests
     [SetUp]
     public void SetUp()
         => _tracker = new ShareTracker(
-            new BeaconInterop(new NoopJsRuntime()),
+            new NoopEventPoster(),
             new StubAnonIdProvider("anon-1"),
             new TestNavigationManager());