feat(launcher): stabilize prepared content updates

tests/AcDream.Launcher.Core.Tests/Installation/PreparedAssetVerificationCacheTests.cs

@@ -67,6 +67,21 @@ public sealed class PreparedAssetVerificationCacheTests : IDisposable
         Assert.Equal(1, _hashCount);
     }
 
+    [Fact]
+    public async Task CacheMissReportsTheExceptionalLongReadBeforeHashing()
+    {
+        LauncherInstallRecordStore store = await CreateInstalledStoreAsync();
+        var statuses = new List<string>();
+
+        Assert.True((await store.LoadAndVerifyAsync(
+            progress: new ImmediateProgress(statuses.Add))).IsVerified);
+
+        Assert.Contains(
+            statuses,
+            status => status.Contains("whole world-data pak", StringComparison.Ordinal)
+                && status.Contains("30 seconds", StringComparison.Ordinal));
+    }
+
     [Fact]
     public async Task ForcedFullVerificationHashesEvenWithAValidCache()
     {
@@ -264,4 +279,9 @@ public sealed class PreparedAssetVerificationCacheTests : IDisposable
             LauncherInstallRecordStore.CurrentBakeToolVersion));
         return store;
     }
+
+    private sealed class ImmediateProgress(Action<string> report) : IProgress<string>
+    {
+        public void Report(string value) => report(value);
+    }
 }