Dock: floating groups, floating title bar menu, translations

- A docked group floats as one window: drag its edge band over the
  drawing or double-click the band. Floating windows hold a stack of
  pallets with splitters; the vertical title bar shows each pallet's
  icon (press one to drag that pallet out). Dragging the bar moves the
  whole window; dropping it on an edge docks or joins it as a group.
- Right-click a floating title bar: Pallets submenu (add or hide
  pallets in the window), Dock left, Dock right.
- Close on a floating bar closes every pallet in the window; its pin
  sets auto-hide for the whole window.
- Older configs with single floating pallets still load.
- Translate the new dock texts (Auto-hide, Dock left/right, New group,
  Pallets, Browser, Node Graph) in all 21 languages.

Co-Authored-By: Claude Opus 5.5 <[email protected]>
Claude-Session: https://claude.ai/code/session_013RyGiMXcsf9HTKfqDxaQGt

src/locale_catalog.rs

@@ -5754,6 +5754,13 @@ pub(super) fn message_attribute(source: &str) -> Option<(&'static str, &'static
         "Invalid count area boundary object. Select a closed polyline consisting of line segments and does not intersect itself." => Some(("count-feature", "invalid-boundary")),
         "Block \"{part}\" cannot be found." => Some(("count-feature", "block-not-found")),
         "Invalid point." => Some(("count-feature", "invalid-point")),
+        "Auto-hide" => Some(("dock", "auto-hide")),
+        "Dock left" => Some(("dock", "dock-left")),
+        "Dock right" => Some(("dock", "dock-right")),
+        "New group" => Some(("dock", "new-group")),
+        "Pallets" => Some(("dock", "pallets")),
+        "Browser" => Some(("dock", "browser")),
+        "Node Graph" => Some(("dock", "node-graph")),
         _ => None,
     }
 }