Overhaul UI with shadcn components and new pages

Add shadcn/ui components (badge, button, card, input, select,
separator). Add company context provider. New pages: Activity,
Approvals, Companies, Costs, Org chart. Restyle existing pages
(Dashboard, Agents, Issues, Goals, Projects) with shadcn components
and dark theme. Update layout, sidebar navigation, and routing.

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

ui/package.json

@@ -11,12 +11,19 @@
   },
   "dependencies": {
     "@paperclip/shared": "workspace:*",
+    "@radix-ui/react-slot": "^1.2.4",
+    "class-variance-authority": "^0.7.1",
+    "clsx": "^2.1.1",
+    "lucide-react": "^0.574.0",
+    "radix-ui": "^1.4.3",
     "react": "^19.0.0",
     "react-dom": "^19.0.0",
-    "react-router-dom": "^7.1.5"
+    "react-router-dom": "^7.1.5",
+    "tailwind-merge": "^3.4.1"
   },
   "devDependencies": {
     "@tailwindcss/vite": "^4.0.7",
+    "@types/node": "^25.2.3",
     "@types/react": "^19.0.8",
     "@types/react-dom": "^19.0.3",
     "@vitejs/plugin-react": "^4.3.4",