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

docs/README.md

@@ -353,6 +353,13 @@ enter your password and click "Confirm" to authorize it. Message and typed-data
 signature requests work the same way, with a "Sign" button, and also require
 your password.
 
+If a transaction or signature popup closes before you answer, for example when
+you click away to copy your password, the request stays open. Closing the popup
+does not turn the request down. Click the AutistMask icon in your browser
+toolbar to bring the request back. Until you answer, the icon opens the request
+instead of your wallet. If several requests are waiting this way, the oldest
+comes first.
+
 A connected site can also ask to switch the wallet's network. A popup shows the
 site's origin, the current network and the requested network. Nothing changes
 unless you click "Switch"; clicking "Reject" or closing the popup leaves