fix: closing a transaction or signature approval window leaves the request pending (closes #673)

Closing a transaction or signature approval window no longer rejects the request; only Cancel does. The browser can close that window when the user clicks away, for example to copy the password from a password manager. The request stays pending and the site gets no answer. Pressing the toolbar button opens the oldest such request, unless an approved attempt still holds it. A Reject the background refuses keeps the window open with the background's message. The worker points the toolbar back at the wallet when it starts.

While such a request waits, the transaction slot stays held, so another site's eth_sendTransaction gets -32002. An address switch still rejects pending approvals with 4001.

Model: opus-5-5

src/popup/index.js

@@ -281,9 +281,9 @@ async function followStoredSettings() {
 // zoom it reports, 170% among them, so once the page has its new width (its
 // resize event) it is measured again, and the window widened again while the
 // page still falls short, three times at most. A window that cannot grow sends
-// no resize event, and the page stops there. The connection prompt can also
-// show in the toolbar popup, whose window is the user's browser window; that
-// one is left alone.
+// no resize event, and the page stops there. An approval can also show in the
+// toolbar popup, whose window is the user's browser window; that one is left
+// alone.
 async function widenApprovalWindow() {
     const page = document.documentElement;
     if (page.scrollWidth <= page.clientWidth) return;