docs(handoff): preview pane next, with the colour-picker trap recorded

HANDOFF.md

@@ -2,35 +2,37 @@
 
 ## State
 
-- Branch `main`, worktree clean. **Seven design commits, unpushed** (push at your checkpoint):
-  `565b8db` DESIGN.md standard · `f2bf577` Tokens.xaml + guard · `84c335a` fonts bundled ·
-  `ffdf3b6` sans wired into the window · `4ef84f2` Controls.xaml · `0275e30` shell
-  (top bar, window, scene strip; mono telemetry).
-- **The app is half-converted on purpose:** theme, shell and readouts are tokenised; the left
-  panel, preview pane and dialogs still carry the old palette.
-- `DESIGN.md` is normative; `Themes/Tokens.xaml` is its implementation. Blue `#38bdf8` is the
-  only interactive accent; red `#ff5451` is live/record only; `#e94560` is retired from chrome.
+- Branch `main`, worktree clean. **Eight design commits, unpushed** (push at your checkpoint):
+  `565b8db` DESIGN.md standard · `f2bf577` Tokens.xaml + guard · `84c335a` fonts ·
+  `ffdf3b6` sans wired · `4ef84f2` Controls.xaml · `0275e30` shell (top bar, window, scene
+  strip, mono telemetry) · `2dbc35b` left panel · `3edb0d1` positive + dark-scrim tokens.
+- **Half-converted on purpose:** theme, shell, left panel and readouts are tokenised; the preview
+  pane and the dialogs still carry the old palette.
+- `DESIGN.md` is normative; `Themes/Tokens.xaml` implements it. Blue `#38bdf8` is the only
+  interactive accent; red `#ff5451` is live/record only; `#e94560` is retired from chrome.
 
 ## Next action
 
-Continue the sweep, one surface per commit, adding each file to
-`DesignTokensTests.Converted_surfaces_carry_no_raw_colour`: `Controls/LeftPanel.xaml` (101 hexes)
-→ `Controls/PreviewPane.xaml` (110) → `Controls/OverlayHost.xaml` + the dialogs (~85) → the
-VM/service brush literals (`MainViewModel.Streaming.cs`, `MainViewModel.Audio.cs`,
-`NotificationService.cs`).
+**`Controls/PreviewPane.xaml`** (110 hexes), then `Controls/OverlayHost.xaml` + dialogs (~85),
+then the VM/service brush literals (`MainViewModel.Streaming.cs`, `.Audio.cs`,
+`NotificationService.cs`). Add each file to `DesignTokensTests.Converted_surfaces_carry_no_raw_colour`.
+
+⚠️ **PreviewPane trap:** it holds a **hardcoded chat-border colour menu** — `MenuItem` rows with
+`Tag="#22c55e"`-style values bound through `EnumToBool` (~line 265). Those hexes are **user data,
+not theme**; tokenising them breaks the picker. Route them through `Models/BorderColorPalette.cs`
+first (TASK 63 precedent), then sweep the rest.
 
 ## Landmines
 
-- **Never tokenize the on-stream renderers or user data:** `Services/AlertRenderer.cs`,
-  `ChatBoxRenderer`, `Compositor/*`, `BrandFlashPresenter`, `Models/BorderColorPalette.cs`,
-  `Models/Source.cs` chat-colour defaults. Those paint the broadcast picture, not app chrome.
-- `Themes/Tokens.xaml` is the only file allowed a raw hex; the guard lists converted files, so a
-  surface that regresses fails the test.
-- A red settings control is a bug now — red means live/record. Sliders and toggles are blue.
+- **Not every hex is a theme colour.** Tokenise app chrome only; leave `BorderColorPalette`,
+  picker `Tag=` values, `Models/Source.cs` chat defaults, and the on-stream renderers
+  (`AlertRenderer`, `ChatBoxRenderer`, `Compositor/*`, `BrandFlashPresenter`) literal.
+- `Themes/Tokens.xaml` is the only file allowed a raw hex; the guard lists converted files.
+- A red settings control is a bug now — red means live/record.
 - Pre-existing: the **full test suite hangs** (WASAPI teardown). Per-class runs are the way.
 
 ## Pending
 
-- **Launch once** to confirm Inter/JetBrains Mono render and the blue accent reads right — the
-  fonts resolve by pack URI, which no test can prove.
+- **Launch once**: confirm Inter/JetBrains Mono render (pack-URI resolution is unprovable in the
+  test host) and that the blue reads right in the room.
 - Vertical-tier camera check; webcam-cadence take in the failing geometry.