feat(client): add UI kit, data layer, app shell, and Table component

- design token system (Atlantis, Kimberly, Powder Ash palette)
- Button, Badge, Input, Select, Card, SidePanel, Breadcrumbs components
- generic typed Table<T> component with loading/empty states
- API data layer: typed fetch client for environments, keys, sessions, scenarios
- Vite dev proxy targeting server on port 13000
- App shell with SidePanel nav and four entity pages (Environments, Keys, Sessions, Scenarios)
- Storybook config with dark/light theme toggle and a11y addon

client/package.json

@@ -6,17 +6,28 @@
   "scripts": {
     "dev": "vite",
     "build": "tsc -b && vite build",
-    "preview": "vite preview"
+    "preview": "vite preview",
+    "storybook": "storybook dev -p 6006",
+    "build-storybook": "storybook build"
   },
   "dependencies": {
     "react": "^19.1.0",
     "react-dom": "^19.1.0"
   },
   "devDependencies": {
+    "@storybook/addon-a11y": "^10.3.5",
+    "@storybook/addon-docs": "^10.3.5",
+    "@storybook/addon-vitest": "^10.3.5",
+    "@storybook/react-vite": "^10.3.5",
     "@types/react": "^19.1.2",
     "@types/react-dom": "^19.1.2",
     "@vitejs/plugin-react": "^4.4.1",
+    "@vitest/browser-playwright": "^4.1.3",
+    "@vitest/coverage-v8": "^4.1.3",
+    "playwright": "^1.59.1",
+    "storybook": "^10.3.5",
     "typescript": "~5.8.3",
-    "vite": "^6.3.1"
+    "vite": "^6.3.1",
+    "vitest": "^4.1.3"
   }
 }