docs(ui): record the open question about layer visibility while a scene is locked

Creator report (2026-11-12): "the creator can still use the layer icon — visibility — if it was
already enabled for that layer". Not reproduced from the obvious paths — with EDIT off the left panel
swaps the layer list for chat, the eye button carries no lock guard, and the preview routes left click
to the zoom box and swallows Ctrl-click — so the note names the two possible answers (a deliberate
exception, or a surface that should be closed) and where to look first. Parked, not acted on.

Scope justification: Assets/starting-background.jpg is outside this unit — the creator's replacement
art, still awaiting their visual check.

docs/ai/ui-surface.md

@@ -145,6 +145,14 @@ Placement math itself is covered by `WindowPlacementTests` (pure function, no HW
   `FormattedText` — **measure, don't guess**) plus the field's padding and border. Guard:
   `ytLive.Tests/GeometryFieldWidthTests.cs`
 - Resolution tiers: 1080p60@12 (default) → 1080p30@10 → 720p60@6 → 720p30@6 → **Vertical 1080p30@10 and 1080p60@12 (9:16, 1080×1920)** — the `@` is the CBR target the encoder is asked to hold, between YouTube's H.264 recommendation and the practitioner sweet spot (its 14/17/8 recommendations are the max, the tier minimums 5/6/3 the step-down floor). Vertical mirrors its landscape pair: same pixel count, same rate. The old flat 8 Mbps was an inherited round number, not a measurement. The composition master frame is **always 1920×1080** — a tier is an output rect + target resolution over that master, so source geometry is never rewritten (no rounding drift). 16:9 tiers use the full frame; vertical tiers use a centered **607×1080** window and the preview dims the cropped side strips at 55% black with an accent outline (semi-crop — the cut area stays visible). A resolution badge in the preview corner shows the active tier. The resolution picker and live readouts (bitrate/FPS/dropped/duration) are in the top-left cell above the layers panel; the bottom bar is an empty height-preserving spacer. Under the picker sits the creator's own **rate box** (Mbps, per tier, persisted as `Video.Rate.<tier>`): the tier chooses geometry, the box chooses bits, clamped at the tier's YouTube minimum and otherwise unbounded because live step-down is the thing that catches a wrong guess. Its tooltip carries YouTube's recommendation for the tier (`Models/RateLadder`). Every consumer — encoder options, step-down policy, clip buffer — reads `MainViewModel.EffectiveQuality`, never the raw tier. A **tooltip** explains finding upload bandwidth — an in-app speed test was deliberately dropped (unreliable). The future encoder crops the master to the rect and scales to the tier's Width×Height
+- **OPEN (creator, 2026-11-12): can a locked scene still be changed through a layer's visibility eye?**
+  Reported as "the creator can still use the layer icon — visibility — if it was already enabled for
+  that layer". Not reproduced from the obvious paths: with EDIT off the left panel swaps the layer list
+  for chat (`LeftPanel.xaml` row 1), the eye button carries no lock guard of its own, the preview routes
+  a left click to the zoom box and swallows Ctrl-click (`PreviewPane.xaml.cs`). So either visibility
+  toggling is meant to stay live while the scene is locked (a deliberate exception to gun-safety), or a
+  surface still exposes it and should be closed. Decide before touching layer locking; check the eye
+  button in `LeftPanel.xaml` (grid column 3) and every `ToggleElementVisibilityCommand` binding first.
 - **Locked output tiers stay visible and clickable.** They are dimmed for non-owners. Choosing one keeps the free tier selected and opens About in-app; only the explicit llamacasty.com link opens a browser.
 - Crash diagnosis: `AppLog` writes startup checkpoints to `%APPDATA%\ytLlive\startup.log`; `App.xaml.cs` logs `DispatcherUnhandledException`/`AppDomain.UnhandledException`. When WPF won't run from WSL, this log is how you find the failure (it caught the `MenuItemRole.Separator` XAML crash and the ComboBox SelectionBoxItem bug). **The log is SIZE-CAPPED (TASK 55, 2026-10-22):** at 5 MB `startup.log` rolls to `startup.1.log` (one rolled copy kept) — the policy lives in `Helpers/LogRotation.cs` as a pure function over a path, so `AppLog`'s 156-call-site surface never changes and the rule is testable on its own. Guard: `ytLive.Tests/AppLogRotationTests.cs`