TASK 24 post-pause polish batch (creator's 8 review issues, 2026-08-15): (1) desktop/game audio volume slider + (2) mute were no-ops — the AudioMixer's gain Func seams defaulted to unity because the VM never passed them; new AudioGainProvider (Services/Audio/) wires MicMuted/MicVolume/GameMuted/GameAudioVolume into the mixer at construction, read live each mix tick, so sliders and mutes are stream-honest; the game bar also scales TRAX locally via new MusicPlayer.LocalGain (UpdateTraxLocalGain on every game volume/mute change + on load) so the creator HEARS the controls work on the music in the headphones. (3) TRAX played once then stopped — OnPlaybackStopped only looped on Position>=Length (unreliable for MediaFoundationReader); now any clean stop rewinds + replays, errors/explicit stops surface via PlaybackEnded; unused using dropped. (4+6) TRAX moved right of Socials in the footer's left cluster (centered under scenes/sources); the mic cluster is now MIC + meter + mute + volume. (5) mic source persists — LayoutStore gains a Settings key/value table (SaveMicSourceName/LoadMicSourceName); the VM saves on pick and restores before the mixer's first Start, so a restart reconnects the same vetted device (green) or reports it missing (yellow). (7) Backdrop's missing trashcan shifted the edit/eye icons right — new HiddenBoolToVisibilityConverter keeps the trash column reserved (Hidden, not Collapsed) so every source row's icons stay in fixed columns. (8) a 1px hairline with top/bottom padding separates scenes from sources in the left panel. Docs in the same commit: ai.md (gains honest + drive TRAX locally, TRAX loops, mic persistence, footer layout), TASKS.md TASK 24, HANDOFF.md shipped state, ViewModels/index.md. ONE integration test: AudioPipelineTests.Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback (real mixer + provider gains through the pipe harness: scaled loopback audible, silence after mute). Build 0 warnings, 197 tests passing

ai.md

@@ -402,26 +402,39 @@ devices, no timers).
   `mixInterval` (default 10 ms) `FillAndMix` reads a chunk from each ring buffer (silence-fills
   underruns), computes the post-filter mic RMS → `AutoDucker` (threshold 0.02, duck ×0.25 / −12 dB,
   attack 0.05, release 0.005, always on), applies the **honest gains** via `Func<double>` seams
-  (`micGain = MicVolume` so mute = 0; `loopbackGain = GameMuted ? 0 : GameAudioVolume`, × duck), mixes
-  mono mic + stereo loopback into interleaved stereo (no clamp — gains are user-owned), and writes the
-  floats to the pipe. `StopStream` → `StopLive()` (closes the pipe → ffmpeg audio EOF) **BEFORE**
-  stopping the frame pump (video EOF) — the reverse order stalls on pipe backpressure. `FfmpegEncoder`
-  itself is untouched; the VM owns the pipe lifecycle.
+  (`micGain = MicMuted ? 0 : MicVolume`; `loopbackGain = GameMuted ? 0 : GameAudioVolume`, × duck),
+  mixes mono mic + stereo loopback into interleaved stereo (no clamp — gains are user-owned), and
+  writes the floats to the pipe. **The gains are wired through `AudioGainProvider`**
+  (`Services/Audio/AudioGainProvider.cs`) — the VM hands its `MicGain`/`LoopbackGain` Funcs to the
+  mixer at construction, read live each tick, so the volume sliders and mute buttons are stream-honest.
+  (Before this wiring the seams defaulted to unity and the controls were decorative.) `StopStream` →
+  `StopLive()` (closes the pipe → ffmpeg audio EOF) **BEFORE** stopping the frame pump (video EOF) —
+  the reverse order stalls on pipe backpressure. `FfmpegEncoder` itself is untouched; the VM owns the
+  pipe lifecycle.
 - **TRAX — free background music (TASK 9):** `MusicPlayer` = NAudio `MediaFoundationReader`
-  (mp3/wav/m4a) → `VolumeWaveProvider16` at the hardcoded **0.20** (no slider) → `WaveOutEvent` on the
-  default device, looping on natural end. It plays to the **desktop**, so the existing loopback captures
-  it: the creator hears it in headphones, the sound-bar meter bounces, and the stream carries it through
-  the loopback channel — **ducked with the game when the mic is hot**. No third mixer input. Footer
-  **TRAX** button beside MIC: status dot (**red** no track / **yellow** loaded stopped / **green**
-  playing) + "TRAX"; **left-click** toggles play/pause (opens the in-app picker via `OpenFileDialog`
-  when no track is loaded); **right-click** always opens the picker (`TraxButton_PreviewMouseRightButtonUp`,
-  `e.Handled = true`, code-behind pattern); tooltip shows the loaded/playing track name or "No track —
-  right-click to choose background music". The picked track persists via **schema v9** single-row
-  `Music` (`TrackPath`/`IsEnabled`) in `LayoutStore`. Known wrinkle (out of scope, future feature):
-  YouTube mutes VODs carrying copyrighted music — "music on live, off VOD" is tabled.
+  (mp3/wav/m4a) → `VolumeWaveProvider16` at the hardcoded **0.20** bed (no slider) → `WaveOutEvent` on
+  the default device, **looping on any clean natural end** (`PlaybackStopped` with `e.Exception == null`
+  → rewind + replay; the earlier `Position >= Length` check was unreliable for `MediaFoundationReader`
+  and let tracks play once then stop). The desktop/game bar scales it locally via `LocalGain` (the VM's
+  `UpdateTraxLocalGain` runs on every `GameAudioVolume`/`GameMuted` change and on TRAX load), so the
+  creator **hears** the game volume slider and mute work on the music in the headphones — matching the
+  stream, where it rides the loopback channel ducked with the game. No third mixer input. Footer
+  **TRAX** button, relocated next to **Socials** in the footer's left cluster (centered under the
+  scenes/sources listboxes) so it no longer sits between MIC and the mic meter: status dot (**red** no
+  track / **yellow** loaded stopped / **green** playing) + "TRAX"; **left-click** toggles play/pause
+  (opens the in-app picker via `OpenFileDialog` when no track is loaded); **right-click** always opens
+  the picker (`TraxButton_PreviewMouseRightButtonUp`, `e.Handled = true`, code-behind pattern); tooltip
+  shows the loaded/playing track name or "No track — right-click to choose background music". The picked
+  track persists via **schema v9** single-row `Music` (`TrackPath`/`IsEnabled`) in `LayoutStore`. Known
+  wrinkle (out of scope, future feature): YouTube mutes VODs carrying copyrighted music — "music on
+  live, off VOD" is tabled.
 - **Mic status dot (`Models/MicStatus.cs`)** on the footer's MIC button: green = `MicConnected`,
   yellow = `MicFailed` (in use/unplugged), red = no mic device at startup (the mixer is never started,
-  so loopback and the game bar can't run either — no capture devices at all).
+  so loopback and the game bar can't run either — no capture devices at all). **The picked mic persists:
+  `LayoutStore`'s `Settings` key/value table stores `MicSourceName` (saved on pick via
+  `SaveMicSourceName`), and the VM restores it at construction BEFORE the mixer's first `Start` — so a
+  restart reconnects the same already-vetted device (green) or reports it missing (yellow), instead of
+  silently falling back to the default endpoint.**
 - **Game audio bar** (desktop/game, only while a full-screen game is up in the preview):
   `IGameAudioDetector` seam (`Services/IGameAudioDetector.cs`), pure `GameAudioHysteresis` (SHOW after
   ~500ms of fullscreen + sound, HIDE after ~1s away from fullscreen, **silence never hides an active
@@ -429,15 +442,18 @@ devices, no timers).
   (floor 0.5%). WPF-free — the VM owns a 250ms `DispatcherTimer` that polls it and flips
   `IsGameAudioBarVisible` (`_gameAudioBarActive || IsMusicPlaying` — music bounces the bar even with no
   game). The bar is **overlaid at the bottom of the preview window** (bottom-center, dark translucent
-  chip, a mirror of the mic bar: meter + mute + volume slider). It's monitoring UI only — it lives in
-  the XAML preview (`MainWindow.xaml`, the PreviewGrid) and never reaches the live output. Relabelled
+  chip, a mirror of the mic bar: meter + mute + volume slider). It's monitoring UI **in the preview
+  grid** — the meter is display-only, but its **volume slider + mute are stream-honest** (via
+  `AudioGainProvider.LoopbackGain`) **and drive TRAX locally** (`MusicPlayer.LocalGain`). Relabelled
   **"Desktop Audio"** (TASK 9) since TRAX rides the same channel.
 - **`WaveToFloat`** (pure, shared): WASAPI mix formats → interleaved float — IEEE float 32-bit direct,
   PCM 16-bit normalized to -1..1, `WaveFormatExtensible` with the IEEE-float subformat GUID
   (`NAudio.Dmo.AudioMediaSubtypes.MEDIASUBTYPE_IEEE_FLOAT`), trailing partial samples ignored.
-- Build **0 warnings**; **196 passing** (DSP/ring-buffer/ducker/resampler/pipe + mixer/hysteresis/
-  game-detector/meter-scale unit tests + the ONE integration test
-  `AudioPipelineTests.Mix_WithFiltersDuckAndGain_Lands_On_AudioPipe`).
+- Build **0 warnings**; **197 passing** (DSP/ring-buffer/ducker/resampler/pipe + mixer/hysteresis/
+  game-detector/meter-scale unit tests + the TASK 9 integration test
+  `AudioPipelineTests.Mix_WithFiltersDuckAndGain_Lands_On_AudioPipe` + the polish-batch integration
+  test `Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback` proving the provider gains reach the
+  pipe and mute silences the loopback).
 
 ### Live frame pipeline (TASK 4 ship step 5 — shipped 2026-08-12, health stats 2026-08-13, plan in TASKS.md)