Add site connection permissions, approval flow, and active address

- Add activeAddress, allowedSites, deniedSites, rememberSiteChoice to
  persisted state
- Replace auto-connect with permission checks: allowed sites connect
  automatically, denied sites are rejected, unknown sites trigger an
  approval popup
- Add approval popup UI with hostname display, active address preview,
  remember checkbox, and allow/deny buttons
- Add ACTIVE/[select] indicator on address rows in the main view to
  set the active web3 address
- Add allowed/denied site list management in settings with delete buttons
- Broadcast accountsChanged to connected dapps when active address changes
- Handle approval window close as implicit denial

src/popup/index.js

@@ -63,9 +63,29 @@ async function init() {
 
     await loadState();
 
+    // Auto-default active address
+    if (
+        state.activeAddress === null &&
+        state.wallets.length > 0 &&
+        state.wallets[0].addresses.length > 0
+    ) {
+        state.activeAddress = state.wallets[0].addresses[0].address;
+        await saveState();
+    }
+
+    // Check for approval mode
+    const params = new URLSearchParams(window.location.search);
+    const approvalId = params.get("approval");
+    if (approvalId) {
+        approval.show(parseInt(approvalId, 10));
+        showView("approve");
+        return;
+    }
+
     $("btn-settings").addEventListener("click", () => {
         $("settings-rpc").value = state.rpcUrl;
         $("settings-blockscout").value = state.blockscoutUrl;
+        settings.renderSiteLists();
         showView("settings");
     });