fix(input-preview): wire Inside-mode + Tooltip-mode render paths

InputPreview was only rendered for PreviewPosition.Top/Bottom (the
DrawConditions IsWindowMode gate). Inside-mode (the default) and
Tooltip-mode had no caller at all because v1.5.6's inline-render path
lived on the deleted ChatLogWindow and was not migrated to the v1.7.0
Components-Layer.

Wire Inside-mode by calling CalculatePreviewHeight + DrawPreview
inline from MainWindow.DrawMainArea between the message-list child
and the input bar, with the message-list height reserved for the
preview block. Wire Tooltip-mode by sampling IsItemHovered() on the
input text widget inside InputBar.DrawInputField (analog to the
existing _isFocused = ImGui.IsItemFocused() idiom on the same line)
and exposing it as WasInputTextHovered; MainWindow opens the tooltip
after _input.Draw when both the hover-flag and PreviewPosition.Tooltip
are active.

Plan-drift acknowledged: the plan stated Plugin.InputPreview is
statically reachable, but the property was declared as an instance
member on Plugin.cs:101. Hoisted to internal static to match the
plan's intention (analog to Plugin.Config); updated the single
external instance-access site in PluginLifecycle.RegisterWindows
to the type-qualified form.

Verified in-game: Inside-mode preview block appears between message
list and input bar on first keystroke; tooltip-mode shows preview on
text-field hover only; Top/Bottom-mode unchanged; empty buffer hides
the preview in all modes. dotnet build clean, dotnet csharpier check
clean.

HellionChat/Ui/InputPreview.cs

@@ -141,7 +141,7 @@ internal sealed class InputPreview : Window
         DrawPreview();
     }
 
-    private void CalculatePreviewHeight()
+    internal void CalculatePreviewHeight()
     {
         // Pre-draw offscreen once to measure actual rendered height; value is
         // consumed next frame by PreDraw() for window sizing.
@@ -162,7 +162,7 @@ internal sealed class InputPreview : Window
         PreviewHeight += IsWindowMode ? ImGui.GetStyle().WindowPadding.Y * 2 : 0;
     }
 
-    private void DrawPreview()
+    internal void DrawPreview()
     {
         using (ImRaii.PushStyle(ImGuiStyleVar.ItemSpacing, Vector2.Zero))
         {