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/tsconfig.json

@@ -10,7 +10,11 @@
     "forceConsistentCasingInFileNames": true,
     "resolveJsonModule": true,
     "isolatedModules": true,
-    "noEmit": true
+    "noEmit": true,
+    "baseUrl": ".",
+    "paths": {
+      "@/*": ["./src/*"]
+    }
   },
   "include": ["src"]
 }