Split popup into one file per view

popup/index.js reduced to ~75 lines: loads state, builds a
shared context object, initializes all views, shows first screen.

Each view in popup/views/:
  helpers.js      — $(), showError, hideError, showView
  welcome.js      — welcome screen
  addWallet.js    — unified create/import recovery phrase
  importKey.js    — private key import
  home.js         — wallet list, total value, address derivation
  addressDetail.js — address view, token list, QR, copy
  send.js         — send form, ENS resolution, tx broadcast
  receive.js      — QR + copy
  addToken.js     — token lookup, common token picker
  settings.js     — RPC endpoint
  approval.js     — dApp approval (stub)

Views communicate via a ctx object with shared callbacks
(renderWalletList, showAddressDetail, doRefreshAndRender, etc).

src/popup/views/addressDetail.js

@@ -0,0 +1,99 @@
+const { $, showView } = require("./helpers");
+const { state, currentAddress } = require("../../shared/state");
+const { formatUsd, getAddressValueUsd } = require("../../shared/prices");
+const QRCode = require("qrcode");
+
+function show() {
+    const wallet = state.wallets[state.selectedWallet];
+    const addr = wallet.addresses[state.selectedAddress];
+    $("address-title").textContent = wallet.name;
+    $("address-full").textContent = addr.address;
+    $("address-copied-msg").textContent = "";
+    $("address-eth-balance").textContent = addr.balance;
+    $("address-usd-value").textContent = formatUsd(getAddressValueUsd(addr));
+    const ensEl = $("address-ens");
+    if (addr.ensName) {
+        ensEl.textContent = addr.ensName;
+        ensEl.classList.remove("hidden");
+    } else {
+        ensEl.classList.add("hidden");
+    }
+    renderTokenList(addr);
+    renderSendTokenSelect(addr);
+    showView("address");
+}
+
+function renderTokenList(addr) {
+    const list = $("token-list");
+    const balances = addr.tokenBalances || [];
+    if (balances.length === 0 && state.trackedTokens.length === 0) {
+        list.innerHTML =
+            '<div class="text-muted text-xs py-1">No tokens added yet. Use "+ Add" to track a token.</div>';
+        return;
+    }
+    list.innerHTML = balances
+        .map(
+            (t) =>
+                `<div class="py-1 border-b border-border-light flex justify-between">` +
+                `<span>${t.symbol}</span>` +
+                `<span>${t.balance || "0"}</span>` +
+                `</div>`,
+        )
+        .join("");
+}
+
+function renderSendTokenSelect(addr) {
+    const sel = $("send-token");
+    sel.innerHTML = '<option value="ETH">ETH</option>';
+    for (const t of addr.tokenBalances || []) {
+        const opt = document.createElement("option");
+        opt.value = t.address;
+        opt.textContent = t.symbol;
+        sel.appendChild(opt);
+    }
+}
+
+function init(ctx) {
+    $("address-full").addEventListener("click", () => {
+        const addr = $("address-full").textContent;
+        if (addr) {
+            navigator.clipboard.writeText(addr);
+            $("address-copied-msg").textContent = "Copied!";
+            setTimeout(() => {
+                $("address-copied-msg").textContent = "";
+            }, 2000);
+        }
+    });
+
+    $("btn-address-back").addEventListener("click", () => {
+        ctx.renderWalletList();
+        showView("main");
+    });
+
+    $("btn-send").addEventListener("click", () => {
+        $("send-to").value = "";
+        $("send-amount").value = "";
+        $("send-password").value = "";
+        $("send-fee-estimate").classList.add("hidden");
+        $("send-status").classList.add("hidden");
+        showView("send");
+    });
+
+    $("btn-receive").addEventListener("click", () => {
+        const addr = currentAddress();
+        const address = addr ? addr.address : "";
+        $("receive-address").textContent = address;
+        if (address) {
+            QRCode.toCanvas($("receive-qr"), address, {
+                width: 200,
+                margin: 2,
+                color: { dark: "#000000", light: "#ffffff" },
+            });
+        }
+        showView("receive");
+    });
+
+    $("btn-add-token").addEventListener("click", ctx.showAddTokenView);
+}
+
+module.exports = { init, show };