Restaurant Finder example: clarify NYC-only local dataset + show friendly “no results” empty state

[roiyz]

The Restaurant Finder example would be more developer-friendly with two small UX improvements:
1. Clarify data scope: Mention that the example searches a local static database containing NYC-only restaurants.
2. Empty-state messaging: When a query yields no matches, show a friendly “no results” message instead of rendering an effectively empty page.

Steps to reproduce
1. Run the Restaurant Finder example
2. In the search box, enter: Top 5 Chinese restaurants in Seattle
3. Click Search

Expected behavior
• A user-friendly message indicating no results were found
• A note explaining that this example uses a local NYC-only dataset, so non-NYC queries won’t return results

Actual behavior
• A blank/empty results page showing only the text:
Top Chinese restaurants in Seattle (see attached image)

Improving the empty state and clarifying the dataset scope would make onboarding smoother and better showcase recommended UI patterns for apps built on this platform.

[roiyz]

I've created a PR to improve the user experience issue described in this item
#345