Dock: review fixes - hover, preview width, stale indexes, config healing

Fixes:
- Hover state no longer drops when the pointer moves up from one strip
  icon, group grip or title bar to the one above: iced handles the
  element above first, so the old element's "left" (None) cleared the
  hover just set. Leave messages now carry the element and only clear
  their own hover.
- The drop preview used the pallets' own widths; it now uses the
  group's width, matching where the pallet lands.
- Group indexes from messages (group grab, splitter) are looked up
  safely, so a message from before a layout change no longer panics.
- Floating placements read from the config are healed (finite, positive,
  at least the minimum size), like the group weights already were.
- The shown group's edge bar is centred in its row: a stack takes its
  height from its first layer, and the icon column was shorter than the
  row. The "Drag to move group" tooltip is removed.

Simplifications (no behaviour change):
- dock_open_at_default / dock_unpeek replace seven copies of "dock on
  the right if unplaced, then reveal" and four of "stop peeking".
- The drop target takes the grab offset as a parameter, so a drag
  update stores its state once.
- dock_set_open, ensure_settings, the shown-index bookkeeping after a
  group is removed and the on-screen width clamp each lose duplication.
- VBarLabel drops options its single caller never varied.
- The drop preview's landing computation is one helper.

Naming and consistency: pallet names in the + menu, the drag ghost and
the floating title bar go through t!(); StripHit::Tab becomes
StripHit::Join; stale comments updated.

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

src/app/commands/blocks.rs

@@ -911,17 +911,7 @@ impl OpenCADStudio {
                 if self.show_external_references {
                     // Always open expanded so the panel is immediately usable;
                     // dock it on the right if the user closed it from the layout.
-                    if !self
-                        .dock
-                        .is_placed(crate::ui::dock::PanelId::ExternalReferences)
-                    {
-                        self.dock.dock(
-                            crate::ui::dock::PanelId::ExternalReferences,
-                            crate::app::config::DockSide::Right,
-                            usize::MAX,
-                        );
-                    }
-                    self.dock_reveal(crate::ui::dock::PanelId::ExternalReferences);
+                    self.dock_open_at_default(crate::ui::dock::PanelId::ExternalReferences);
                     self.refresh_xref_manager();
                 }
             }

src/app/commands/count.rs

@@ -236,12 +236,9 @@ impl OpenCADStudio {
         self.count_palette.show = open;
         self.ribbon.set_count_palette(open);
         if open {
-            if !self.dock.is_placed(id) {
-                self.dock.dock(id, crate::app::config::DockSide::Right, usize::MAX);
-            }
-            self.dock_reveal(id);
-        } else if self.dock_peek == Some(id) {
-            self.dock_peek = None;
+            self.dock_open_at_default(id);
+        } else {
+            self.dock_unpeek(id);
         }
     }
 

src/app/commands/layerprops.rs

@@ -679,15 +679,7 @@ impl OpenCADStudio {
                     // rearrange themselves on upgrade for a panel they have
                     // not asked for.
                     let id = crate::ui::dock::PanelId::Browser;
-                    if !self.dock.is_placed(id) {
-                        // dock() clamps an out-of-range index to the end of
-                        // the edge, so this appends below whatever is there.
-                        self.dock
-                            .dock(id, crate::app::config::DockSide::Right, usize::MAX);
-                    }
-                    // Open expanded so it is usable straight away; the pin
-                    // button still collapses it.
-                    self.dock_reveal(id);
+                    self.dock_open_at_default(id);
                     self.command_line
                         .push_output(crate::t!("Browser opened.").as_ref());
                 } else {

src/app/commands/pdf_underlay.rs

@@ -374,16 +374,11 @@ impl OpenCADStudio {
             "POINTCLOUDMANAGER" => {
                 let id = crate::ui::dock::PanelId::PointCloudManager;
                 self.pc_manager.show = true;
-                if !self.dock.is_placed(id) {
-                    self.dock.dock(id, crate::app::config::DockSide::Right, usize::MAX);
-                }
-                self.dock_reveal(id);
+                self.dock_open_at_default(id);
             }
             "POINTCLOUDMANAGERCLOSE" => {
                 self.pc_manager.show = false;
-                if self.dock_peek == Some(crate::ui::dock::PanelId::PointCloudManager) {
-                    self.dock_peek = None;
-                }
+                self.dock_unpeek(crate::ui::dock::PanelId::PointCloudManager);
             }
             "_PCUNCROP" =>self.edit_selected_point_clouds(i, "POINTCLOUDUNCROP", |data| data.croppings.clear()),
             "_PDFULUNCLIP" => {

src/app/commands/sheet_set.rs

@@ -577,12 +577,9 @@ impl OpenCADStudio {
         self.sheet_set.show = on;
         self.ribbon.set_sheet_set(on);
         if on {
-            if !self.dock.is_placed(id) {
-                self.dock.dock(id, crate::app::config::DockSide::Right, usize::MAX);
-            }
-            self.dock_reveal(id);
-        } else if self.dock_peek == Some(id) {
-            self.dock_peek = None;
+            self.dock_open_at_default(id);
+        } else {
+            self.dock_unpeek(id);
         }
     }