fix: WebLN QR fallback for anon users

[Soxasora]

Description

Fixes #1758
When a WebLN wallet request fails (eg. cancelling a transaction) it can't be re-requested until next reload, throwing an error and prompting an invoice retry with QR that fails if the user is not logged in.

This fix checks for 'me' on useWalletPayment, throwing a new AnonWalletError that can be caught during QR fallback to show both the WebLN client and the QR payment

Screenshots

Screen.Recording.2025-02-10.at.09.45.51.mov

Additional Context

Fix specifically applied for WebLN

Checklist

Are your changes backwards compatible? Please answer below:
Yes, only affects WebLN wallet

On a scale of 1-10 how well and how have you QA'd this change and any features it might affect? Please answer below:
7, more testing

For frontend changes: Tested on mobile, light and dark mode? Please answer below:
n/a

Did you introduce any new environment variables? If so, call them out explicitly here:
No

[Soxasora]

While thinking about it, the major errors that this would ignore are already handled: Invoice cancel, Invoice expiration. If I'm not mistaken, retryPaidAction checks for Invoice failed and Invoice already paid, in the context of anon payment this shouldn't really happen as every paidAction generates a new invoice

Edit: Tested with alby extension on timeout, on close and on error

[ekzyis]

Mhh, it's a bit hard to understand the implications of these changes. For example, I am worried if the priority of the WebLN wallet makes a difference for these changes here.

I think a better way to fix #1758 is to make useWalletPayment aware of if we're logged in or not.

If we're not logged in, try to pay with WebLN if available (typeof window.webln !== 'undefined') and ignore the rest of the code. That it currently might not ignore it for anons because WebLN might have been enabled (wallets.length > 0) is the bug we should fix imo. 99% of our code for payments assumes you're logged in and thus that anons will never hit that code.

What anons can do in comparison to stackers is very limited (no sender and receiver fallbacks, no retries etc.) so I suspect if we (continue to) handle anons during payments immediately, it will be much easier to implement, maintain, read etc.

[ekzyis]

It can also fail for other reasons, like if the user closed the prompt etc. so the error message can be misleading.

I think it should just reuse the WebLN error message:

Suggested change

	throw new WalletError('cannot re-enable wallet')
	throw new WalletError(err.message)

[Soxasora]

Thanks a lot for the correct redirection, now we call WebLN's sendPayment when QR shows up! But only if we reached QR stage because of AnonWalletError that gets thrown by useWalletPayment if the user attempting to pay is Anon.

I think it's the correct behavior and gives a choice, if anything we could 'await' for sendPayment to throw an error to show the QR if we ever change idea.
Thanks again ^^