chore: install @radix-ui/react-popover dependency

Required for the new compact popover-based layout settings UI.

🤖 Generated with [Claude Code](https://claude.com/claude-code)

Co-Authored-By: Claude Sonnet 4.5 <noreply@anthropic.com>

package.json

@@ -23,6 +23,7 @@
     "@radix-ui/react-dialog": "^1.1.15",
     "@radix-ui/react-dropdown-menu": "^2.1.16",
     "@radix-ui/react-hover-card": "^1.1.15",
+    "@radix-ui/react-popover": "^1.1.15",
     "@radix-ui/react-progress": "^1.1.8",
     "@radix-ui/react-scroll-area": "^1.2.10",
     "@radix-ui/react-slot": "^1.2.4",