Outsource custom GUI class components to dashgui library

Move reusable GUI primitives (PanelTile, EditablePanelTile, base Tile,
ElevatedPill, SingleLineTextEdit) into the shared dashgui package and
consume them via a file: dependency. EditablePanelTile now accepts an
onError prop so error notification stays app-side.

package.json

@@ -23,6 +23,7 @@
     "@reduxjs/toolkit": "^2.12.0",
     "@shopify/draggable": "^1.2.1",
     "notistack": "^3.0.2",
+    "dashgui": "file:../dashgui",
     "react": "^19.2.8",
     "react-dom": "^19.2.8",
     "react-redux": "^9.3.0",