feat(display): answer the Display controls through the store with UiSegmented

The Display panel, the dock's style buttons and the clean-view exit call
the display store's actions, and DisplayBindings connects their handlers
to it, replacing the bindDisplayControls listeners. The detection
allocation and 3D model coverage choices render through a new kit
UiSegmented, which takes v-model, options, label,
stacked and disabled, and adds a keyboard policy, item classes and
per-option attributes.

Shell element fields and facade accessors that only the old listeners
read are removed. The package boundaries now own UiSegmented and the
UiPanel kit files, and the format scope drops the deleted test.

scripts/package-boundaries.json

@@ -121,6 +121,10 @@
       "src/ui/stores/firstRun.js",
       "src/firstRunCopy.js",
       "src/ui/kit/UiButton.vue",
+      "src/ui/kit/UiSegmented.vue",
+      "src/ui/rail/RailPanel.vue",
+      "src/ui/kit/UiPanel.vue",
+      "src/ui/kit/UiPanelToggle.vue",
       "src/ui/stores/panelChrome.js",
       "src/ui/rail/PanelCollapseButton.vue",
       "src/ui/rail/panelState.js"
@@ -564,7 +568,7 @@
   },
   "display-controls": {
     "exports": ["./ui/display"],
-    "modules": ["src/ui/displayControls.js", "src/ui/segmentedControl.js"],
+    "modules": ["src/ui/displayControls.js"],
     "external": []
   },
   "visual-effects": {