Dock: floating menu at the pointer, hover-only bar buttons, Allow docking, clip pallets

- The floating title bar's right-click menu opens where the pointer is,
  flipped to stay on screen; the Pallets submenu sits beside it.
- Close and pin on a floating title bar only show while it is hovered,
  as on docked title bars.
- New Allow docking check in that menu: off, dragging the window (or a
  pallet out of it) only floats it, never docks it on an edge.
- Floating windows and stacked pallets clip their content, so a pallet
  sized below its content no longer draws outside its frame.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_013RyGiMXcsf9HTKfqDxaQGt

locales/ru-RU/opencadstudio.ftl

@@ -6155,6 +6155,7 @@ count-feature =
     .invalid-point = Недопустимая точка.
 
 dock =
+    .allow-docking = Разрешить закрепление
     .auto-hide = Автоскрытие
     .dock-left = Закрепить слева
     .dock-right = Закрепить справа