# HANDOFF — 2026-10-08

## Branch
- main (no feature branch)

## Dirty files (NOT mine — the in-flight "pinned chat" work unit; do NOT commit or co-edit)
- `Models/YouTube.cs`
- `ViewModels/MainViewModel.Chat.cs`
- `Controls/LeftPanel.xaml` (pinned-message UI; restored via `git stash pop` after this commit)
- Untracked: `Helpers/RelayCommandGeneric.cs`

## What just happened (2026-10-08 zoom build)
- **TASK 51 booked (webcam background Remove + Blur as a v1 requirement):** `TASKS/task-51-webcam-bg-effects.md` created; TASKS.md row 51 + the two prior "background removal excluded" rulings (`~line 180` webcam cadence + "Out of product — permanently") reversed 2026-10-08. NVIDIA VFX SDK stays ruled out. Implementation queued after the zoom build.
- **Zoom rebuilt from "loupe + output crop" into a REAL composited layer:**
  - New `Models/ZoomSceneElement.cs` (z-index 1 above the background, below every other layer; `IsZoomActive` flips `Kind` Static→Dynamic; never persisted, never shown in the layers list or element template). `SceneElement.IsZoomLayer` virtual added.
  - New `ViewModels/MainViewModel.Zoom.cs`: `ActivateZoom` (all shapes CENTERED on the click, clamped to the master), move/dismiss, `HealZoomLayers`/`EnsureZoomLayer` (load + `AddScene`), `BuildZoomFrame` (resolves live-capture-under-art exactly like `SceneCompositor.Render`, single-slot cache keyed on frame identity+Epoch+box ints so the per-tick resolver allocates nothing idle), and the pure static `ZoomFrameBuilder.Build` (2x bilinear sample of the box/2 window centered on the box centre).
  - `BuildCompositorOptions` now ALWAYS returns the tier crop (internal = test seam); zoom-as-crop branch + `RebuildDimRectsForZoom` old version removed. `ResolveOutputFrameCore` gained the `ZoomSceneElement` case; output composites the zoom like any layer.
  - Preview: backdrop images wrapped in `BackdropLayer`; `ZoomBox` moved INSIDE `OverlayCanvas` under the element Layers (renders below layers = honest preview); `ZoomVisualBrush` now samples `BackdropLayer` at `(X+W/4, Y+H/4, W/2, H/2)` + `Stretch=Fill` (2x); element template + LeftPanel list collapse `IsZoomLayer`.
- Tests: `ZoomBoxInteractionTests` rewritten (center-anchor for all shapes, placeholder at Elements[1], Kind flips, tier crop asserted, dismiss resets); new `ZoomFrameBuilderTests` = the genuine-magnification proof (4-band backdrop, box straddling two bands, all output pixels must be the center band → a 1x or mis-positioned window fails hard). `LayerReorderPersistenceTests` updated: cross-type reload compares persisted elements only (the zoom placeholder never persists), and the real-mouse drag targets rows by ITEM (the collapsed zoom row shifts container indices — the handlers hit-test visually so real dragging is unaffected).
- Full suite: **405 passed / 0 failed / 0 warnings**.

## Zoom feature state
- Models: `ZoomState.cs`, `ZoomShape.cs` (Circle/VerticalRectangle/HorizontalRectangle), `ZoomSceneElement.cs` (TASK 51 build).
- ViewModel (all in `MainViewModel.Zoom.cs`): activation/move/dismiss + layer healing + `BuildZoomFrame`; `MainViewModel.cs` core no longer holds zoom methods.
- Output: zoom layer composited at z-index 1; output crop = tier; dim rects show the box frame while active.
- Preview: `ZoomBox` samples `BackdropLayer` at 2x, circle→ellipse clip, rect/square outline per shape; `LeftPanel` hides the placeholder row via `IsZoomLayer`.

## Known issues / follow-ups
- **Background "Use default background" toggle still not working** (carried from 2026-10-07): binding exists (`UseDefaultBackground`), VM handler invalidates bake; investigate Source background logic when time permits.
- `AudioPipelineTests.Mix_HonorsProviderGains_AndGameMute_KillsTheLoopback` flaked once in a full-suite run (passed in isolation 27/27 and in the final full run) — treat as machine-contention flake, not a zoom regression.
- `RealMouseDrag_OnTheLayerList_PersistsTheReorder` needs an interactive desktop (documented) — it passes when the window is live; don't read a failure there as a code bug without re-running.

## Next step
- User runs the app live/test to eyeball the zoom: right-click preview → centered box per shape, output contains a genuine 2x magnified backdrop under the other layers, dimming + outline correct, layers list unchanged. Then TASK 51 (webcam background Remove + Blur) implementation per `TASKS/task-51-webcam-bg-effects.md`, and the background-toggle investigation if still open.