Do not show settled-hold-invoice as success: order is not finished until Lightning payment succeeds

[Catrya]

The app currently treats the settled-hold-invoice status as a successful final state.
This is incorrect and misleading.

settled-hold-invoice occurs when the seller releases the escrow, but the order is not finished yet. At this point, Mostro is still attempting to pay the buyer’s Lightning invoice.

• If the payment succeeds, the order later transitions to success.
• If the payment fails, the order remains in settled-hold-invoice.

Despite this, the app already shows settled-hold-invoice as success, which can confuse users and hide the fact that the buyer has not received their sats yet.

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Actual behavior

• The app shows settled-hold-invoice as success.
• The buyer may believe the trade is completed even if the Lightning payment failed.
• If the payment fails, there is no clear indication in the UI that the order is still pending or requires action.

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Expected behavior

• The app should only show success when it receives the final success status.
• settled-hold-invoice should be treated as an intermediate state, not a final one.
• The UI should clearly communicate that the Lightning payment is still in progress.

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Proposed UI change

Introduce a buyer-only UI state representing the period between escrow release and successful Lightning payment.

For example: “Paying sats”

This state should:

• be visible only to the buyer,
• indicate that sats are being paid,
• not be shown as success,
• and clearly communicate that the process is still ongoing.