Add transaction confirmation screen and password modal

New send flow: Send → Confirm → Password → Broadcast.

Send view: collects To (with ENS resolution), Amount, Token.
"Review" button advances to confirmation. No password field.

Confirm Transaction view: shows From, To (with ENS name),
Amount (with USD value), and runs pre-send checks:
- Scam address warning (checked against local blocklist)
- Self-send warning
- Insufficient balance error (disables Send button)

Password modal: full-screen overlay, appears only after user
clicks Send on the confirmation screen. Decrypts the wallet
secret, signs and broadcasts the transaction. Wrong password
is caught inline.

scamlist.js: hardcoded set of known scam/fraud addresses
(Tornado Cash sanctioned, drainer contracts, address
poisoning). Checked locally, no external API.

src/popup/index.js

@@ -13,6 +13,7 @@ const addWallet = require("./views/addWallet");
 const importKey = require("./views/importKey");
 const addressDetail = require("./views/addressDetail");
 const send = require("./views/send");
+const confirmTx = require("./views/confirmTx");
 const receive = require("./views/receive");
 const addToken = require("./views/addToken");
 const settings = require("./views/settings");
@@ -38,6 +39,7 @@ const ctx = {
     showImportKeyView: () => importKey.show(),
     showAddressDetail: () => addressDetail.show(),
     showAddTokenView: () => addToken.show(),
+    showConfirmTx: (txInfo) => confirmTx.show(txInfo),
 };
 
 async function init() {
@@ -52,13 +54,13 @@ async function init() {
 
     await loadState();
 
-    // Initialize all view event handlers
     welcome.init(ctx);
     addWallet.init(ctx);
     importKey.init(ctx);
     home.init(ctx);
     addressDetail.init(ctx);
     send.init(ctx);
+    confirmTx.init(ctx);
     receive.init(ctx);
     addToken.init(ctx);
     settings.init(ctx);