feat: stackLimit prop to limit number of toasts displayed when collapsed

[jamestickle]

Feature

Adds stackLimit prop functionality as requested #1175

Summary

Added a stackLimit prop to the Toast component to allow users to define a maximum number of toasts to display when stacked, but display all when expanded. The additional toasts are hidden behind the visible stacked toasts, keeping existing behaviour of smooth collapsing and expanding.

Why This Change?

This avoids bugs/issues like #1171 by default. Improves the user experience and flexibility of the stacked toast component by keeping the screen cleaner, which is likely the user's intention in using stacked in the first place.

Key Features

• Updated Toast component to accept and handle a new stackLimit prop.
• User defined value is used when greater than 1, otherwise default of 10. This prevents bad UX.
• Updated TypeScript definitions to include the new stackLimit prop.
• Additional test for existing stack behaviour with stackLimit set
• Updated playground to display stackLimit as an option

Usage example

<ToastContainer autoClose={false} stacked stackLimit={2} />

stackLimit.demo.mov

Affected Files

• src/types.ts → add stackLimit type and description
• src/components/ToastContainer.tsx → stackLimit logic
• playground/src/components/App.tsx → handleNumPicker and stackLimit option
• playground/src/components/ContainerCode.tsx → stacked, stackLimit and limit options now displayed
• playground/src/components/constants.ts → add stacked
• src/core/toast.cy.tsx → new test
• src/addons/use-notification-center/NotificationCenter.cy.tsx and src/addons/use-notification-center/useNotificationCenter.ts → use local files instead of 'react-toastify' import

Checklist

• Feature implemented and tested
• Code follows the project's style guidelines
• Used prettier before committing
• No breaking changes introduced

Additional Information

• Added handleNumPicker function for limit and stackLimit in playground to simplify handleRadioOrSelect into handleRadio.
• Display both limit when > 0 and stackLimit when > 1 in ToastContainer in playground.
• Use local files for imports in Notification Center tests.