Token auto-discovery, tx history, balance polling, EIP-6963, UI overhaul

Major changes:
- Fetch token balances and tx history from Blockscout API (configurable)
- Remove manual token discovery (discoverTokens) in favor of Blockscout
- HD address gap scanning on mnemonic import
- Duplicate mnemonic detection on wallet add
- EIP-6963 multi-wallet discovery + selectedAddress updates in inpage
- Two-tier balance refresh: 10s while popup open, 60s background
- Fix $0.00 flash before prices load (return null when no prices)
- No-layout-shift: min-height on total value element
- Aligned balance columns (42ch address width, consistent USD column)
- All errors use flash messages instead of off-screen error divs
- Settings gear in global title bar, add-wallet moved to settings pane
- Settings wells with light grey background, configurable Blockscout URL
- Consistent "< Back" buttons top-left on all views
- Address titles (Address 1.1, 1.2, etc.) on main and detail views
- Send view shows current balance of selected asset
- Clickable affordance policy added to README
- Shortened mnemonic backup warning
- Fix broken background script constant imports

src/popup/views/home.js

@@ -1,4 +1,4 @@
-const { $, showView } = require("./helpers");
+const { $, showView, showFlash, balanceLinesForAddress } = require("./helpers");
 const { state, saveState } = require("../../shared/state");
 const { deriveAddressFromXpub } = require("../../shared/wallet");
 const {
@@ -33,15 +33,17 @@ function render(ctx) {
         html += `</div>`;
 
         wallet.addresses.forEach((addr, ai) => {
-            html += `<div class="address-row py-1 border-b border-border-light cursor-pointer hover:bg-hover px-1" data-wallet="${wi}" data-address="${ai}">`;
+            html += `<div class="address-row py-1 border-b border-border-light cursor-pointer hover:bg-hover" data-wallet="${wi}" data-address="${ai}">`;
+            html += `<div class="text-xs font-bold">Address ${wi + 1}.${ai + 1}</div>`;
             if (addr.ensName) {
                 html += `<div class="text-xs font-bold">${addr.ensName}</div>`;
             }
-            html += `<div class="text-xs break-all">${addr.address}</div>`;
-            html += `<div class="flex justify-between items-center">`;
-            html += `<span class="text-xs">${addr.balance} ETH</span>`;
-            html += `<span class="text-xs text-muted">${formatUsd(getAddressValueUsd(addr))}</span>`;
+            const addrUsd = formatUsd(getAddressValueUsd(addr));
+            html += `<div class="flex text-xs">`;
+            html += `<span class="shrink-0" style="width:42ch">${addr.address}</span>`;
+            html += `<span class="text-right text-muted flex-1">${addrUsd}</span>`;
             html += `</div>`;
+            html += balanceLinesForAddress(addr);
             html += `</div>`;
         });
 
@@ -62,27 +64,25 @@ function render(ctx) {
             e.stopPropagation();
             const wi = parseInt(btn.dataset.wallet, 10);
             const wallet = state.wallets[wi];
+            const newAddr = deriveAddressFromXpub(
+                wallet.xpub,
+                wallet.nextIndex,
+            );
             wallet.addresses.push({
-                address: deriveAddressFromXpub(wallet.xpub, wallet.nextIndex),
+                address: newAddr,
                 balance: "0.0000",
                 tokenBalances: [],
             });
             wallet.nextIndex++;
             await saveState();
             render(ctx);
+            ctx.doRefreshAndRender();
         });
     });
 
     renderTotalValue();
 }
 
-function init(ctx) {
-    $("btn-settings").addEventListener("click", () => {
-        $("settings-rpc").value = state.rpcUrl;
-        showView("settings");
-    });
-
-    $("btn-main-add-wallet").addEventListener("click", ctx.showAddWalletView);
-}
+function init(ctx) {}
 
 module.exports = { init, render };