fix(ui): #353 — the stack-count entry takes the one-line draw path; RightAligned engages and the edit flicker dies

RightAligned only applies on UiField's single-line renderer; the entry
was falling into the multi-line path (ignoring the alignment AND
re-scrolling its extents per keystroke — the reported edit flicker).
A 14 px numeric entry is single-line by construction; OneLine = true
routes it correctly. The 233 now sits flush against the slider per the
authored HJustify=2.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

src/AcDream.App/UI/Layout/SelectedObjectController.cs

@@ -180,6 +180,12 @@ public sealed class SelectedObjectController : IRetainedPanelController
             // flush against the slider at X=50 on the same row — the count
             // reads right-adjacent to the bar, retail's look. UiField
             // already supports it; the importer does not carry HJustify.
+            // OneLine is REQUIRED for the alignment: RightAligned only
+            // applies on the single-line draw path, and the multi-line
+            // path's per-keystroke scroll-extent churn was also the edit
+            // flicker the user reported. A 14 px numeric entry is
+            // single-line by construction.
+            _stackSizeEntry.OneLine = true;
             _stackSizeEntry.RightAligned = true;
             _stackSizeEntry.Selectable = true;
             _stackSizeEntry.ClearOnSubmit = false;