Fix: scaling window size difference

docs/TAURI_RUNTIME_TESTING.md

@@ -122,6 +122,9 @@ An issue touching Tauri runtime behaviors must satisfy all requirements before `
   API mismatch)
 - verify window resize uses consistent coordinate units (no accumulated drift over 20 scale changes)
 - no runtime command/type error from position updates (e.g. `set_position` expects integer coords)
+- at the same slider scale value, main window size is consistent across packs (`default`, `ferris`,
+  `demogorgon`) within 1px rounding tolerance
+- no white strip/background bleed is visible along any overlay window edge on dark desktop background
 
 ## Settings Window Checklist