fix(ypp): refresh 403'd on every real call — drop the auditDetails part (needs a partner scope)

Creator: 'when I attempt to refresh my YPP page, I get an error about not being
able to reach YouTube. Seriously?' Real log: channels.list failed (403) x3.

Root cause #1 (the 403): channels.list?mine=true&part=statistics,auditDetails,
contentDetails returns 403 insufficientPermissions when the token lacks the
youtubepartner-channel-audit scope — which the auditDetails part ALONE requires,
per the docs ('A request that retrieves the auditDetails part ... must provide an
authorization token that contains the youtubepartner-channel-audit scope'). That
scope is MCN partner tooling with a 2-week token-revocation rule; the app must not
hold it. TASK-39's 'current scopes suffice, no re-consent' slice-1 claim was wrong
for this part; mock-fake tests never touched the real API, so it shipped green and
403'd every refresh since 2026-09-22.
https://developers.google.com/youtube/v3/docs/channels/list

Fix: part=statistics,contentDetails only; standing flags removed from
ChannelStatsService -> YppStatSnapshot surface -> YppTrackerViewModel -> drawer,
replaced by an honest deep-link row ('Channel standing isn't exposed to YouTube
apps — check the Earn page'). YppSnapshot standing columns stay (schema-stable,
always false). channels.list failures now log the response BODY — the bare code
could not name insufficientPermissions, which is what made this undiagnosable.

Root cause #2 (found by the new Good Dog, masked by the 403): statistics come back
as JSON STRINGS ('350'); raw GetInt64() throws. Tolerant ReadInt64 (ValueKind-first;
JsonElement.TryGetInt64 THROWS on strings — type-in, not try-type).

Good Dog: ChannelStatsServiceTests.CaptureCurrent_RequestsNoAuditDetails_AndStillParsesTheSnapshot
(URL asserts no auditDetails + snapshot parses); YppPullOutTests fixture updated.
Recipes for both 403/scope and statistics-strings entered in MyMistakes.md.

Also shipped in the same commit (shared PreviewPane.xaml + ai.md): the audio-sync
status dot removal from the #77 feedback round (creator: 'what is the point of the
status light? Lose it') — IntToSyncBrushConverter deleted with it.

verify.sh gate: 0 warnings, 316/316 pass, scope-check clean.

ytLive.Tests/ChannelStatsServiceTests.cs

@@ -0,0 +1,84 @@
+using System;
+using System.Net;
+using System.Text;
+using System.Threading.Tasks;
+using Xunit;
+using ytLive.Services;
+
+namespace ytLive.Tests;
+
+/// <summary>
+/// TASK 39 root-cause guard (2026-09-23): the YPP refresh's channels.list call
+/// must NOT request the `auditDetails` part — that part alone requires the
+/// `youtubepartner-channel-audit` scope the app doesn't (and mustn't) hold, and
+/// the whole request 403s `insufficientPermissions` over it (this exact failure
+/// sat in the real logs for weeks). One integration test: the snapshot still
+/// parses subscribers/views/videos/uploads from `statistics,contentDetails`, and
+/// the URL never mentions auditDetails.
+/// </summary>
+public class ChannelStatsServiceTests
+{
+    private sealed class RecordingHandler : HttpMessageHandler
+    {
+        public string? LastBody;
+        public Func<HttpRequestMessage, string?>? ResponseSelector;
+        public readonly System.Collections.Generic.List<string> Requests = new();
+
+        protected override Task<HttpResponseMessage> SendAsync(
+            HttpRequestMessage request, CancellationToken cancellationToken)
+        {
+            Requests.Add($"{request.Method.Method} {request.RequestUri}");
+            LastBody = request.Content?.ReadAsStringAsync().GetAwaiter().GetResult();
+            return Task.FromResult(new HttpResponseMessage(HttpStatusCode.OK)
+            {
+                Content = new StringContent(
+                    ResponseSelector?.Invoke(request) ?? "{}", Encoding.UTF8, "application/json"),
+            });
+        }
+    }
+
+    [Fact]
+    public async Task CaptureCurrent_RequestsNoAuditDetails_AndStillParsesTheSnapshot()
+    {
+        var auth = new YouTubeAuthService("test-client", "test-secret");
+        auth.SetSession(new Models.YouTubeChannel
+        {
+            AccessToken = "acc-123",
+            TokenExpiry = DateTime.UtcNow.AddHours(1),
+        });
+
+        var handler = new RecordingHandler
+        {
+            ResponseSelector = request =>
+                request.RequestUri!.ToString().Contains("channels")
+                    ? """
+                      {"items":[{"id":"UC-1","statistics":{"subscriberCount":"350","viewCount":"12345","videoCount":"42"},
+                                 "contentDetails":{"relatedPlaylists":{"uploads":"UPL"}}}]}
+                      """
+                    : """
+                      {"items":[
+                        {"snippet":{"publishedAt":"2026-08-01T00:00:00Z"}},
+                        {"snippet":{"publishedAt":"2026-09-01T00:00:00Z"}},
+                        {"snippet":{"publishedAt":"2025-01-01T00:00:00Z"}}
+                      ]}
+                      """,
+        };
+
+        var service = new ChannelStatsService(auth, new System.Net.Http.HttpClient(handler));
+        var snapshot = await service.CaptureCurrentAsync();
+
+        Assert.NotNull(snapshot);
+        Assert.Equal(2, handler.Requests.Count);
+        Assert.StartsWith("GET ", handler.Requests[0]);
+        Assert.Contains("channels?mine=true", handler.Requests[0]);
+        Assert.Contains("part=statistics,contentDetails", handler.Requests[0]);
+        Assert.DoesNotContain("auditDetails", handler.Requests[0]);
+        Assert.Contains("playlistItems", handler.Requests[1]);
+
+        Assert.Equal(350, snapshot!.SubscriberCount);
+        Assert.Equal(42, snapshot.VideoCount);
+        Assert.Equal(12_345, snapshot.TotalViews);
+        Assert.Equal(2, snapshot.UploadsLast90Days);
+        Assert.False(DateTime.UtcNow - snapshot.CapturedAtUtc > TimeSpan.FromMinutes(1));
+    }
+}

ytLive.Tests/YppPullOutTests.cs

@@ -61,10 +61,6 @@ public sealed class YppPullOutTests
                 VideoCount = 42,
                 TotalViews = 12_345,
                 UploadsLast90Days = 2,
-                CommunityGuidelinesGoodStanding = true,
-                CopyrightStrikesGoodStanding = true,
-                ContentIdClaimsGoodStanding = true,
-                OverallGoodStanding = true,
             };
 
             var vm = new YppTrackerViewModel(
@@ -81,7 +77,6 @@ public sealed class YppPullOutTests
             Assert.True(vm.HasSnapshot);
             Assert.Equal(350, vm.SubscriberCount);
             Assert.Equal(2, vm.UploadsLast90Days);
-            Assert.True(vm.OverallGoodStanding);
             Assert.Equal("Test Channel", vm.DisplayName);
             Assert.Equal("350 / 500", vm.Tier1SubsText);
             Assert.Equal("350 / 1,000", vm.Tier2SubsText);