feat: US-010 — Projects sidebar tree view and project detail routing

Co-Authored-By: Claude Opus 4.6 <noreply@anthropic.com>

package.json

@@ -50,8 +50,10 @@
     "@radix-ui/react-collapsible": "^1.1.12",
     "@radix-ui/react-dialog": "^1.1.15",
     "@radix-ui/react-dropdown-menu": "^2.1.16",
+    "@radix-ui/react-select": "^2.2.6",
     "@radix-ui/react-separator": "^1.1.8",
     "@radix-ui/react-slot": "^1.2.4",
+    "@radix-ui/react-switch": "^1.2.6",
     "@radix-ui/react-tooltip": "^1.2.8",
     "@radix-ui/react-visually-hidden": "^1.2.4",
     "@tanstack/react-query": "^5.90.21",