Merge #1425: gui(send): display max calculated amount w/ 8 decimals

7ab6d05f0bc0c00cfe9a160e8320f4c7de1ae212 gui(send): display max calculated amount w/ 8 decimals (pythcoiner)

Pull request description:

  fixes #1424
  ![image](https://github.com/user-attachments/assets/ffdfc45e-3162-4bc9-ae80-cd4379cb0981)

ACKs for top commit:
  edouardparis:
    utACK 7ab6d05f0bc0c00cfe9a160e8320f4c7de1ae212

Tree-SHA512: 9c4dc7f2ccf2a8c2e6b62a0d628f70bc9a357b70960d215b64d3c695e32610158ee875c78d41e6c942c87cc9fe9633f77e509056d4cf85614c98ee05bf926eab

liana-gui/src/app/view/spend/mod.rs

@@ -8,7 +8,7 @@ use iced::{
 
 use liana::{
     descriptors::LianaPolicy,
-    miniscript::bitcoin::{bip32::Fingerprint, Amount, Network},
+    miniscript::bitcoin::{bip32::Fingerprint, Amount, Denomination, Network},
 };
 
 use liana_ui::{
@@ -379,14 +379,14 @@ pub fn recipient_view<'a>(
                             .width(Length::Fixed(110.0)),
                     )
                     .push_maybe(if is_max_selected {
+                        let amount_txt = Amount::from_str_in(&amount.value, Denomination::Bitcoin)
+                            .ok()
+                            .map(amount_as_string)
+                            .unwrap_or(amount.value.clone());
                         Some(
-                            Container::new(
-                                text(amount.value.clone())
-                                    .size(P1_SIZE)
-                                    .style(color::GREY_2),
-                            )
-                            .padding(10)
-                            .width(Length::Fill),
+                            Container::new(text(amount_txt).size(P1_SIZE).style(color::GREY_2))
+                                .padding(10)
+                                .width(Length::Fill),
                         )
                     } else {
                         None

liana-ui/src/component/amount.rs

@@ -39,7 +39,7 @@ pub fn unconfirmed_amount_with_size<'a, T: 'a>(a: &Amount, size: u16) -> Row<'a,
 //
 
 // Format a BTC amount as a string for display.
-fn amount_as_string(a: Amount) -> String {
+pub fn amount_as_string(a: Amount) -> String {
     let amount = a.to_btc().to_string();
 
     // Reformat the integer portion of the amount with space separation.