w0xlt

Thanks @furszy for the review. The suggestions were addressed in https://github.com/bitcoin/bitcoin/commit/948651da4f88b3479f36f48163f09bf2af4d2c92 and https://github.com/bitcoin/bitcoin/commit/3c96b258e530bf0f99a4a0c7ddc2d5dbca732119.

https://github.com/bitcoin/bitcoin/pull/25616#discussion_r921916024 addressed in https://github.com/bitcoin/bitcoin/commit/7cbfa1335bd89d5831e916672e57aa8601b12bb4.

https://github.com/bitcoin/bitcoin/pull/25616#pullrequestreview-1041617804 and https://github.com/bitcoin/bitcoin/pull/25616#pullrequestreview-1041856598 were addressed in https://github.com/bitcoin/bitcoin/commit/087959d6e92ed37b72b86dbbc9b0ff052a6c5a75.

Thanks for the review @shaavan, but a rebase was needed. Rebased and changed the code to use `util::Result` which replaced the `BResult`. @jonatack I used the suggested format in this...

CI error seems unrelated. `interface_usdt_validation.py` worked fine on my machine. https://cirrus-ci.com/task/6722929781112832

Rebased.

@luke-jr Yes, it will need to be further discussed if this concept proves to be valid. In this PR, all descriptor wallets support silent transactions as the `SILENT_PAYMENT` flag can...

@luke-jr @JeremyRubin Thanks for the comments. The current version deliberately does not implement a new address/descriptor format. This requires a separate discussion and changes in wallet behavior. And it doesn't...

I created a short and simple tutorial on how to make silent payments on signet. https://gist.github.com/w0xlt/72390ded95dd797594f80baba5d2e6ee

@prusnak It s not well documented as well as being discussed. In the current implementation, for simplicity, [only the first input is used.](https://github.com/w0xlt/bitcoin/blob/8f616acf868bbc75b31bf5170c40fd9957c08e91/src/wallet/spend.cpp#L665) There is a suggestion by @RubenSomsen to...