fix(recording-dialog): +20% height so the file-name box is not clipped; unhook full-screen hook on shutdown

RenameRecordingDialog was 230px tall for ~225px of stacked content —
the file-name textbox clipped (old client area ~193px). Height is now 276
(+20%). Integration test shows the real dialog in the app host and asserts
the textbox bottom edge stays inside the client area; the dialog's Icon moved
to the explicit /ytLive;component/ URLC form MainWindow already uses so tests
can construct it (root-relative /Assets/... only resolves in production via
Application.ResourceAssembly).

Dependency fix: MainViewModel.Shutdown() now calls
_fullScreenDetector.StopWatching(). The global EVENT_SYSTEM_FOREGROUND hook
was never unhooked; after VM collection the next foreground event invoked a
garbage-collected WinEventProc delegate, crashing the whole test run. Harmless
in production (exits the process) but fatal in the multi-window test host.

Reference: WPF WinEvent hook lifecycle guidance — SetWinEventHook callbacks
must be unhooked before the owning object is collected (obs-projector
fullscreen-detection pattern).

RenameRecordingDialog.xaml

@@ -1,8 +1,8 @@
 <Window x:Class="ytLive.RenameRecordingDialog"
         xmlns="http://schemas.microsoft.com/winfx/2006/xaml/presentation"
         xmlns:x="http://schemas.microsoft.com/winfx/2006/xaml"
-        Title="Rename Recording" Height="230" Width="460"
-        Icon="/Assets/llamacasty-icon.png"
+        Title="Rename Recording" Height="276" Width="460"
+        Icon="/ytLive;component/Assets/llamacasty-icon.png"
         WindowStartupLocation="CenterOwner" ResizeMode="NoResize"
         ShowInTaskbar="False" Background="#1a1a2e">