Feat(rnpsw): add example project

[Jokotoye18]

Description

This pull request adds a demo project showcasing how to integrate and use the react-native-paystack-webview package.
The demo provides a working example for developers to quickly understand how to implement the library in their React Native apps.

Key features:

• Basic payment flow using Paystack WebView
• Sample UI with a "Pay" button
• Clean, beginner-friendly structure with comments

Issue URL

N/A – This is a new feature contribution and not tied to any existing issue.

Before and After

Before	After
Visual: N/A – There was no demo project previously.
Functionality: N/A	Demo project added to showcase how to integrate and use react-native-paystack-webview. Includes basic payment flow and UI. 🎥 Watch the demo video on Imgur

[Jokotoye18]

@just1and0 this PR adds the demo project as described. Please review when you get a chance 🙏

[just1and0]

Thank a lot @Jokotoye18 for working on this PR! I see how helpful this will be for the community. I'll review and revert.

[just1and0]

Thanks for making this update. I added some reviews.

[just1and0]

@Jokotoye18 we have a contribution guideline, you can reference that here rather that listing a new one.

See contribution.md

[just1and0]

This isn't resolved yet

[mosoakinyemi]

[nit] - @Jokotoye18 Could we rename the /demo folder to /example for clarity?

[mosoakinyemi]

Asides the tiny recommended changes, PR LGTM ✅
And I think we should add 2 or so screenshots from the demo/example repo @Jokotoye18.

Approving for now, trusting you'll make the necessary adjustments.
Thanks for the contribution @Jokotoye18! 🙌🏼

[Jokotoye18]

I made the required changes @just1and0, please can you review again.
cc: @mosoakinyemi

[Jokotoye18]

I made the required changes @just1and0, please can you review again. cc: @mosoakinyemi

This one is still waiting for approval @just1and0

[mosoakinyemi]

@just1and0 I’m good with merging this as it just adds stuff to the /example dir
Lemme know if you have any questions/comments

[just1and0]

Lgtm

[just1and0]

@Jokotoye18 please can you resolve the pending comments

[just1and0]

This isn't resolved yet