diag(build): per-build GUID stamp + resolve/blit timing split (take-6 attribution failure)

Take 6 measured render 35-41ms — WORSE than take 5's 25.5 — and the run could
not be attributed to a binary: exe mtime != build contents (incremental builds
serve stale exes; a source edit without rebuild is a silent old binary). Three
takes of a perf saga had been judged against builds nobody could prove.

- ytLive.csproj GenerateBuildStamp target: fresh GUID per compile (writes
  obj/BuildStamp.g.cs -> Helpers/BuildStamp.Id/BuiltLocal). Deliberately defeats
  incremental lies: every 'dotnet build' recompiles the app project.
- Wordmark shows the id as a superscript (TopBar.xaml, x:Static, 9px grey
  BaselineAlignment=Superscript); startup.log records 'Build <id> (compiled
  <time>)' so every take is cross-readable with the visible UI.
- FramePump stats split the tick: 'avg render Xms (resolve Y), avg submit Z' —
  the resolver is timed separately (wrapper resolver on per-tick paths; bake
  keeps the raw one) so take 7 names the hot half of 'render' with data.
- Fixed a latent transition-clock bug found on the way: lastTick now restarts
  every frame (the branch rework had restarted it only during transitions,
  letting a transition begun after idle complete instantly on its first Tick).

ONE integration test family: BuildStampTests (unit: shape) +
BuildStampDisplayTests (RealApp, namescoped FindName on TopBar proves the
wordmark SHOWS the id). 47/47 per-class green, clean build 0 warnings. Docs
same commit. User's top-bar/session spec (re-sent twice) + settled Q&A
decisions folded into HANDOFF Unit B — next work unit after take 7 verdict.

ai.md

@@ -171,7 +171,7 @@ C# / WPF (.NET 8) following MVVM:
 | `Models/` | Plain data types — Scene, Source (incl. `ClipShape`, `IsMirrored`, `VideoImageSource`), QualityOption, StreamConfig, StreamHealth, YouTubeChannel, ChatMessage, **Socials (`SocialService` enum + `SocialEntry`/`SocialsConfig` + `SocialServiceIcons`) — the social bar** |
 | `ViewModels/` | MainViewModel — `public partial class`, one file per functional area (Scenes, Background, Webcam, Audio, Trax, Socials, Streaming, Chat, Overlays, Account, License, Recording — split complete, see `ViewModels/index.md`); **Chat.cs is a thin delegating facade over `Services/ChatOverlayLayer.cs` (Commit G, first true decomposition)**; GoLiveViewModel, ReuseImageViewModel, CameraPickerViewModel, **SocialsDialogViewModel** |
 | `Services/` | YouTube OAuth2, stream/broadcast management, live chat polling, LayoutStore (SQLite), **SocialValidator (`ISocialValidator` seam + `HttpSocialValidator` default)**, **webcam: `VideoFrame` seam + `CameraDeviceInfo`/`ICameraEnumerator`/`ICameraFrameSource` interfaces + `MediaCaptureCameraEnumerator`/`MediaCaptureFrameSource` (WinRT) + `CameraManager`**, **screen capture: `IFullScreenDetector`/`Win32FullScreenDetector` + `IScreenCaptureSource`/`ScreenCaptureFrameSource` (WinRT GraphicsCapture) + `ScreenCaptureManager` + `ScreenCaptureSourceFactory` + `Direct3D11Helper`/`CaptureInterop` (COM bridges)**, **media source: `IMediaFrameSource` + `MediaVideoSource` (spawns ffmpeg `rawvideo` BGRA decode) + `MediaVideoSourceManager` (refcount-by-path session owner) + pure `RawVideoFrameReader` + `IDecodeProcess`/`FfmpegDecodeProcess` process seam (binary-stdout mirror of `IEncoderProcess`; see "Media source")**, **compositor: `SceneCompositor` + `CompositorOptions` + pure `StretchMath` + `StaticPixelCache` (see "Scene compositor")**, **audio: `IAudioSource` seam + `WasapiLoopbackAudioSource`/`WasapiMicAudioSource` (NAudio WASAPI) + `AudioMixer` + pure `AudioLevelMeter`/`WaveToFloat`/`VoiceFilterChain`/`LowShelfFilter`/`HighShelfFilter`/`NoiseGate`/`Compressor`/`AutoDucker`/`AudioRingBuffer`/`TinyResampler`/`AudioSyncDelay` + `MusicPlayer` + `IAudioPipeWriter`/`NamedPipeAudioWriter` (see "Live audio capture")**, **encoder: `IFfmpegEncoder`/`FfmpegEncoder` + `IEncoderProcess`/`FfmpegEncoderProcess` + `IFfmpegLocator`/`FfmpegLocator` + pure `FfmpegArgs`/`FfmpegProgressParser`/`FfmpegEncoderPicker` + the `FramePump` frame producer (see "Live encoder" + "Live frame pipeline")**, **notifications: `INotificationService` seam (`AppNotificationSeverity` Info/Success/Warning/Error) + `NotificationService` (Notification.Wpf toasts, see "Toast notifications")** |
-| `Helpers/` | ViewModelBase (INotifyPropertyChanged), RelayCommand, ImageCache, AppLog (file logger), FocusPreservingListBox, OAuthCredentials, **TokenStore (DPAPI session persistence)**, visibility converters |
+| `Helpers/` | ViewModelBase (INotifyPropertyChanged), RelayCommand, ImageCache, AppLog (file logger), FocusPreservingListBox, OAuthCredentials, **TokenStore (DPAPI session persistence)**, **BuildStamp (per-build GUID generated by `GenerateBuildStamp` in ytLive.csproj — wordmark superscript + startup.log line, 2026-09-04)**, visibility converters |
 | `Themes/` | `Controls.xaml` — the single dark-theme source, merged once in `App.xaml` (see `Themes/index.md`) |
 | `MainWindow.xaml` | Dark theme; layout: top bar (controls), center (preview + live controls below), left (scenes/sources), right (chat), bottom (gear + stream stats + resolution) |
 
@@ -679,7 +679,10 @@ scene each tick, resolves every element to its latest frame, composites it into
 and paces frames into the encoder at the tier's FPS. **rawvideo is stamped by ARRIVAL:** ffmpeg assigns
 pts from frame order at the declared fps — supply rate = output speed. A starved producer (pump < fps)
 ships a time-lapse, truncated file with NO error (take-2 lesson, 2026-09-01); the pump therefore logs
-`FramePump stats: n/target frames per 5s, avg render Xms submit Yms` so a slow stage names itself. **Pattern — everything is a constructor-injected
+`FramePump stats: n/target frames per 5s, avg render Xms (resolve R), avg submit Yms` so a slow stage names itself — and since 2026-09-04 so does the BUILD: every build gets a GUID stamped
+into `Helpers/BuildStamp` (csproj `GenerateBuildStamp` target, fresh per compile — no lying incremental build), shown as the wordmark superscript and logged at startup
+("Build xxxxxxxx (compiled ...)"). **Take 6 (stamp-less, ambiguous): render 35-41ms with slice 3 built or not unknown — attribution is why the stamp exists; takes 7+ are
+readable.** If the breakdown says resolve dominates, the suspects are pre-cached chat/config thrash or the web frame; if blit dominates, the general-path element sizes. **Pattern — everything is a constructor-injected
 seam:** `Func<Scene?>`, `Func<SceneElement, VideoFrame?>` resolver, `Func<CompositorOptions>`,
 `Func<EncoderOptions?>`, `Func<IFfmpegEncoder>`, `Action<string>` log, and an injectable pacing delay
 (default `Task.Delay`; tests inject `Task.Yield`). The pump is free of WPF and of the capture managers.