feat(ui): add current-launch logs tab

Add Live Chat and Logs tabs to the non-edit left panel. Expose a bounded process-local AppLog feed so the newest messages appear first without importing earlier startup.log contents or changing file logging.

Ref: https://obsproject.com/forum/resources/understanding-obs-studio-log.473

docs/ai/ui-surface.md

@@ -103,7 +103,7 @@ The app is a **director's control surface**, not an editor. This replaces the OB
 
 **Current layout (2026-10-26 redesign commits):** `MainWindow` has a top bar and health banner, then a two-column work area with a fixed 360px left column and preview column. Its top row holds stream readouts/resolution on the left and the five-scene strip above the preview; the lower row holds the left panel and central preview. The bottom bar is now only a height-preserving spacer.
 
-- **Left panel:** `EditingActive` is an explicit `EDIT` toggle, not a mode inferred from `StreamStatus`. On = scene layers + properties; off = YouTube chat. Go Live turns editing off and stopping restores it; recording does not automatically switch it off. The staged scene is the preview/edit target; `LiveScene` is the program output.
+- **Left panel:** `EditingActive` is an explicit `EDIT` toggle, not a mode inferred from `StreamStatus`. On = scene layers + properties; off = a two-tab panel with **Live Chat** first/default and **Logs** second. Logs is a read-only, newest-first view of up to 500 `AppLog` entries captured in this process; it does not load older `startup.log` contents or change file logging/rotation. Go Live turns editing off and stopping restores it; recording does not automatically switch it off. The staged scene is the preview/edit target; `LiveScene` is the program output.
 - **Settings is a right-edge drawer, not a modal (2026-11-01):** the gear rail tab opens `Controls/SettingsDrawer` in the same animated-width stack as Stream Settings / YPP / Socials / TEST (`SettingsDrawerOpen`, exclusive with the other four). Categories are section headings with their controls indented under them — Zoom holds *Zoom view shape* and *Zoom box follows*. The app menu (Report Bug / Feature Request / About) hangs off a **right-click on the LlamaCasty wordmark**; left-click still opens About. The modal shell keeps only Bug / Feature / About, which is why it no longer needs a scroll viewer.
 - **Top bar:** the `EDIT` toggle sits beside the REC/ON-AIR session controls; the brand and account surfaces remain at the sides. Its **right edge aligns with the layers panel below** (`TopBar` column 0 is a fixed **352** = work-area margin 8 + 360px column − the bar's own 16px padding), so the button and the panel share an edge. The **settings gear moved to the preview rail** (2026-11-01): first tab, orange (`Brush.Attention`), gear icon only — left-click opens the app menu (Settings / Bug / Feature / About), right-click goes straight to App Settings.
 - **Preview gestures (2026-11-01):** *edit mode* — left selects/drags/resizes, right opens the context menu, **Ctrl+right toggles the zoom box**. *Preview mode* — **left toggles the zoom box**, right opens the context menu; **Ctrl+right does nothing at all** (no chord while live or recording — one hand, always). ⚠️ **Both the Down and the Up event must be handled for a Ctrl+right-click**: WPF's `PopupControlService` opens a context menu on right-button-**up**, so suppressing only the down event leaves the menu appearing under the gesture (found 2026-11-01 in edit mode). Menus exist on the webcam layer and the backdrop; every other layer right-clicks through to the backdrop menu. Left-dragging with the zoom box open moves it, in both modes. **Ctrl-down closes it**: pressing Ctrl while the box is open dismisses it, so the same hand that opened it can put it away (`MainWindow_PreviewKeyDown`; the box cannot cancel itself on creation because Ctrl is already down before it exists). **Follow mode** is a Settings pill, default **off = Anchor**: with Follow on, dragging re-anchors the capture to the box centre (`ZoomFollowsBox`, persisted as the `Zoom.FollowBox` setting). **The gesture activates the box at the cursor**, not merely dismisses it: `ActivateZoom` no longer refuses when idle (it used to return unless `IsLive || IsRecording`, and `ToggleZoom` only ever dismissed — so the gesture did nothing at all outside a session until 2026-11-01). The social bar consumes its own click (toggle top ⇄ bottom), and the preview's tunnelling handler steps aside for it — otherwise the bar is unclickable in preview mode and drags the layer beneath it in edit mode.