feat: Adding dark mode, cleaning the UI a small bit, adding a link to the API documentation, and linting the code. (#2182)

# What does this PR do?

This PR adds a few enhancements:
- Dark mode 
- A dark mode icon
- Adds a link to the API documentation
- Adds prettier and a linter to the code 
- Aligning the default text
- Linted the code 

## Before:
![Screenshot 2025-05-15 at 3 57
15 PM](https://github.com/user-attachments/assets/996db083-4a4f-4683-a2b4-e7c09de96135)

## After (dark mode):
![Screenshot 2025-05-15 at 3 57
50 PM](https://github.com/user-attachments/assets/9d45d26b-2449-4a5f-813e-29e07e94b793)

[//]: # (If resolving an issue, uncomment and update the line below)
[//]: # (Closes #[issue-number])

## Test Plan
[Describe the tests you ran to verify your changes with result
summaries. *Provide clear instructions so the plan can be easily
re-executed.*]

[//]: # (## Documentation)


Related to https://github.com/meta-llama/llama-stack/issues/2085

---------

Signed-off-by: Francisco Javier Arceo <farceo@redhat.com>

llama_stack/ui/package.json

@@ -6,19 +6,23 @@
     "dev": "next dev --turbopack",
     "build": "next build",
     "start": "next start",
-    "lint": "next lint"
+    "lint": "next lint",
+    "format": "prettier --write \"./**/*.{ts,tsx}\"",
+    "format:check": "prettier --check \"./**/*.{ts,tsx}\""
   },
   "dependencies": {
     "@radix-ui/react-dialog": "^1.1.13",
+    "@radix-ui/react-dropdown-menu": "^2.1.14",
     "@radix-ui/react-separator": "^1.1.6",
     "@radix-ui/react-slot": "^1.2.2",
     "@radix-ui/react-tooltip": "^1.2.6",
     "class-variance-authority": "^0.7.1",
     "clsx": "^2.1.1",
     "lucide-react": "^0.510.0",
-    "next": "^15.3.2",
-    "react": "^19.1.0",
-    "react-dom": "^19.1.0",
+    "next": "15.3.2",
+    "next-themes": "^0.4.6",
+    "react": "^19.0.0",
+    "react-dom": "^19.0.0",
     "tailwind-merge": "^3.3.0"
   },
   "devDependencies": {
@@ -29,6 +33,9 @@
     "@types/react-dom": "^19",
     "eslint": "^9",
     "eslint-config-next": "15.3.2",
+    "eslint-config-prettier": "^10.1.5",
+    "eslint-plugin-prettier": "^5.4.0",
+    "prettier": "^3.5.3",
     "tailwindcss": "^4",
     "tw-animate-css": "^1.2.9",
     "typescript": "^5"