fix: refusing a From address the wallet does not hold moves nothing (closes #609)

Sign & Send wrote its refusal of a From address the selected wallet does not
hold onto the password error line, which reserves one line. The sentence runs
to about three, so it pushed Sign & Send down.

The refusal now has its own box above the password field, its sentence fixed
in index.html, holding its space from the first paint and only made visible,
as #583 did for the other
refusals. Drawing the screen and each press hide it again. A Chrome test
writes the other wallet into the stored selection, reopens the popup onto the
screen, presses Sign & Send and checks that nothing was broadcast and nothing
moved.

Model: opus-5-5

src/popup/views/confirmTx.js

@@ -320,6 +320,7 @@ function show(txInfo) {
     $("confirm-tx-password").value = "";
     hideError("confirm-tx-password-error");
     setVisible("confirm-network-changed-error", false);
+    setVisible("confirm-from-address-error", false);
     setVisible("confirm-fee-bound-error", false);
 
     // Gas estimate — show placeholder then fetch async
@@ -661,6 +662,7 @@ function init(_ctx) {
     $("btn-confirm-send").addEventListener("click", async () => {
         // A press shows only its own refusal, if any.
         setVisible("confirm-network-changed-error", false);
+        setVisible("confirm-from-address-error", false);
         setVisible("confirm-fee-bound-error", false);
 
         const wallet = state.wallets[state.selectedWallet];
@@ -686,11 +688,7 @@ function init(_ctx) {
         // address selected.
         const addr = wallet.addresses.find((a) => a.address === pendingTx.from);
         if (!addr) {
-            showError(
-                "confirm-tx-password-error",
-                "The selected wallet does not hold the From address above, " +
-                    "so nothing was sent. Please go back and send again.",
-            );
+            setVisible("confirm-from-address-error", true);
             return;
         }