fix: the wallet's own send shows its amount to four decimal places (closes #522)

ConfirmTx and the wait, success and error screens printed the text from
Send's amount field as typed or as Max filled it in: `0.5 ETH`, `.5 ETH`, or
`1.234147890123456789 ETH` after Max, where TxApproval shows a site's send
as `0.5000 ETH`. ConfirmTx now writes the amount as TxApproval does: parsed
at the scale it is encoded with, written back as plain decimal text, and cut
by truncateAmountNeverZero(). It hands the status screens a copy carrying
that text. The transaction is still signed for the exact amount, which stays
on the pending transaction, and the USD value is priced from it. A saved
confirmation screen whose amount is not text is no longer redrawn.

Model: opus-5-5

tests/persistedFieldContract.test.js

@@ -477,6 +477,19 @@ const CONTRACT = [
                 views: ["confirm-tx"],
                 restored: false,
             },
+            // The amount line splits the amount to cut it to four decimals.
+            {
+                value: {
+                    pendingTx: {
+                        token: "ETH",
+                        from: ADDRESS,
+                        to: ADDRESS,
+                        amount: 42,
+                    },
+                },
+                views: ["confirm-tx"],
+                restored: false,
+            },
             // A chain id naming no network has no explorer to link to.
             {
                 value: {