Implement personal_sign and eth_signTypedData_v4 message signing

Replace stub error handlers with full approval flow for personal_sign,
eth_sign, eth_signTypedData_v4, and eth_signTypedData. Uses toolbar
popup only (no fallback window) and keeps sign approvals pending across
popup close/reopen cycles so the user can respond via the toolbar icon.

src/shared/tokenList.js

@@ -10,6 +10,11 @@ const { debugFetch } = require("./log");
 const COINDESK_API = "https://data-api.coindesk.com/index/cc/v1/latest/tick";
 
 const TOKENS = [
+    {
+        address: "0xC02aaA39b223FE8D0A0e5C4F27eAD9083C756Cc2",
+        symbol: "WETH",
+        decimals: 18,
+    },
     {
         address: "0xdAC17F958D2ee523a2206206994597C13D831ec7",
         symbol: "USDT",