Add OnRowClick EventCallback to QuickGrid

[Copilot]

Add OnRowClick EventCallback to QuickGrid

• You've read the Contributor Guide and Code of Conduct.
• You've included unit or integration tests for your change, where applicable.
• You've included inline docs for your change, where applicable.
• There's an open issue for the PR that you are making. If you'd like to propose a new feature or change, please open an issue to discuss the change or find an existing issue.

Add row click handling to QuickGrid component

Description

Adds OnRowClick parameter to QuickGrid enabling row click event handling.

Changes:

• OnRowClick parameter of type EventCallback<TGridItem>
• row-clickable CSS class with cursor: pointer applied when delegate is set
• E2E tests for callback triggering and cursor styling

Usage:

<QuickGrid Items="@people" OnRowClick="HandleRowClick">
    <PropertyColumn Property="@(p => p.Name)" />
</QuickGrid>

@code {
    void HandleRowClick(Person person) => Console.WriteLine($"Clicked: {person.Name}");
}

Fixes #44899

---

💬 We'd love your input! Share your thoughts on Copilot coding agent in our 2 minute survey.

[dotnet-policy-service]

Greetings! You've submitted a PR that modifies code that is shared with https://github.com/dotnet/runtime . Please make sure you synchronize this code with the changes in that repo!