Add manual coin selection for channel opening

[MaxHillebrand]

Feature Request

Manual coin selection is very useful to open a channel with only carefully selected utxos, which is good for privacy. I would like to have the option to select exactly which coins to use in the input of the channel opening transaction. Especially together with the Use All Funds option, this can create 1 input || 1 output channel openings.

[pm47]

Have you considered using several distinct wallets ? You could do pretty much that. Granted, on a single phone that would require enabling gdrive backups which may be a no-go for you.

Side note: on Phoenix, since channels are always funded by our node, you don't leak any UTXOs when creating channels. You can also choose to empty your wallet over LN, which means that your UTXO set remains completely untouched during the whole lifecycle of the app. Caveat: in its current version Phoenix is less private than Eclair Mobile wrt LN payments.

[MaxHillebrand]

Several wallets won't help much, because I will want to send and receive payments from any one of these channels. If I have 5 channels in 5 wallets, then I would have to provide 5 invoices to get the same routing success.

My usecase is rather simple:

1. Send bitcoin from external wallet to eclair onchain
2. Use exactly that coin that just got received to open a channel, 1 input || 1 output transaction

This is a generic user flow, and it would increase privacy tremendously.