feat: display global notification on API request failures (fixes #2106)

[keshav0479]

Description

Fixes #2106

This PR introduces a global error handling mechanism in ApiWebClient. Previously, network timeouts or coordinator unreachable errors resulted in silent failures. Now, these failures dispatch a ROBOSATS_API_ERROR custom event.

The main App component has been updated to listen for this event and display a user-friendly Snackbar alert at the bottom of the interface.

Changes

• Refactored ApiWebClient.ts to use a central request helper with error catching.
• Added a global Snackbar and useEffect listener in App.tsx to handle the error broadcasts.
• Verified style compliance via pre-commit (Prettier and ESLint passed).

Testing

• Simulated "Offline" mode in browser DevTools.
• Confirmed the "Coordinator unreachable" alert appears correctly when an API call is triggered.
• 

[KoalaSat]

Ey @keshav0479 this looks great! Can you please also take into consideration frontend/src/services/api/ApiAndroidClient/index.ts ?

[keshav0479]

Thanks for the review @KoalaSat! I completely missed the Android client.

I have just pushed a commit that applies the same error broadcasting logic to frontend/src/services/api/ApiAndroidClient/index.ts. I also took the opportunity to refactor the Android client to use a centralized request helper (similar to the Web client) to reduce code duplication.
I verified that the error notification triggers correctly on both Web and simulated Android bridge events.

[KoalaSat]

@keshav0479 awesome thank you! can you please also remove comments? we usually try to avoid them unless for extremely complex code

[keshav0479]

Done! I've removed the comments to keep the code clean

[KoalaSat]

Great job @keshav0479 !

Please accept a small tip for your work. Share here a LN invoice with a long expiration date for 90,000 sats

[keshav0479]

Thank you @KoalaSat! I really appreciate the review and the tip.

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[RobosatsDevFund]

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