Improve Network Error Handling UX

[puneetnith28]

Problem

When a network error occurs, the NetworkError.svelte component only displays a static message with no recovery option.

• Users must manually refresh the entire page to retry.
• There is no distinction between a server error and the device being fully offline.
• There is no visibility into the raw error for debugging purposes.

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What It Affects

• NetworkError.svelte Component shown on all network failures
• +error.svelte Global error page that renders NetworkError
• en-US.json and it-IT.json Missing i18n strings for new UI elements

[VaiTon]

I am not convinced this is relevant enough for our use case. I'd be inclined to not implement this, unless there is request from users.